40 Hollywood Actors Who Underwent Crazy Transformations for a Movie Role

The life of a Hollywood celebrity is more demanding than most people realize. We tend to focus on the money and the glitz when we look at movie stars. However, acting can be a challenging profession in many different ways. They frequently have to pick up new talents – such as learning a language or playing an instrument – and go through significant physical changes to make their roles realistic.

While prosthetics and fat suits are frequently adopted, a movie can seem far more genuine if the actors have worked hard to truly embody their roles. For example, they might undertake a rigorous tanning routine, grow a full beard, or shave their heads completely bald

Let's check out some of the most remarkable changes actors have undergone.

Chris Hemsworth: Thor

Few actors have approached a role with the same enthusiasm and success as Chris Hemsworth when he was chosen as Thor. Hemsworth worked out with former Navy SEAL trainer Duffy Gaver for the first movie, using an old-school bodybuilding technique focusing on Hemsworth's shoulders and arms.

Hemsworth put on a total of 20 pounds, building the basis for a physique he's kept in peak shape for Thor's recurrent roles in The Avengers and other sequels, like Thor: The Dark World.

Christian Bale: The Machinist

Mechanic Trevor Reznik, who has acute insomnia, was portrayed by Christian Bale in the 2004 film The Machinist. Reznik loses a lot of weight due to sleep deprivation and thins out considerably. As a result, Bale had to severely cut down his food intake to look like the character.

The actor went on an extreme diet to shed 63 pounds, eating one can of tuna and an apple daily for over four months. The star's exercise routine included intense resistance training and aerobic exercises.

Chris Pratt: Guardians of the Galaxy

Chris Pratt, the Guardians of the Galaxy star, lost 60 pounds of fat in six months by consistently working out for four hours each day. When Pratt went to the Marvel movie audition, he weighed over 300 pounds. At the time, he was best known for his role as Andy Dwyer in Parks and Recreation.

Duffy Gaver, a personal trainer, and Phil Goglia, a nutritionist, partnered with Marvel to help Pratt train for the Guardians of the Galaxy role. Goglia changed Pratt's diet, increasing it to 4,000 calories daily and adding a ton of water. Pratt had put on weight for his Parks and Recreation persona, but after getting in shape for Marvel, he’s now determined to remain trim.

Jake Gyllenhaal: Southpaw

Gyllenhaal worked out six hours every day for six months to build 15 pounds of muscle for his role as a middleweight fighter in the movie Southpaw. As a result, he lost 30 pounds before stepping into the role of boxer Billy Hope.

"We basically made him into a beast," the film's director Antoine Fuqua said of the actor's transition. “The sacrifice that you infuse with your body and the time commitment required, it's not something that you will be excited to do again.” Gyllenhaal described his demanding preparation for the part as "a significant commitment."

Matthew McConaughey: Dallas Buyers Club

Matthew McConaughey's remarkable weight loss is a fascinating part of the film Dallas Buyers Club. He lost more than 40 pounds for the fictionalized account of AIDS patient Ron Woodroof, who takes action against the US government for providing other patients with unapproved medication.

Despite worries from some about how the intense 25-day shoot may affect his health, McConaughey claimed that he felt he had more than enough energy—at least mentally—to finish it. Matthew McConaughey won the Best Actor award at the 2014 Oscars for his portrayal of Woodroof. 

Natalie Portman: Black Swan

Natalie Portman had a grueling schedule for her part as a ballerina in Black Swan. The slim actress had a rigid diet of little more than almonds and carrots and shed 20 pounds for the job. She also put in eight hours per day of practice.

Natalie, who won an Oscar for playing the obsessively ambitious dancer, exuded perfection. However, she was both physically and emotionally exhausted from the movie. It was the first time she had become so consumed by a character that it had the power to weaken her.

Jared Leto: Dallas Buyers Club

To play his part in Dallas Buyers Club, Jared Leto shed an incredible 40 pounds. To play Rayon, a trans woman with HIV and later AIDS, he dropped to just 114 pounds. He said that his weight change had permanent effects. "It alters the way you sit, the way you walk, and the way you think." So naturally, this has resulted in some health problems over time.

Thankfully, his devotion and hard work paid off as Dallas Buyers Club garnered numerous honors, and he received an Oscar for Best Supporting Actor.

Tom Hardy – Bronson

Tom Hardy is renowned for his dramatic physical changes, but what he underwent to play "the most dangerous prisoner in Britain" takes the prize. Hardy claimed that he only had five weeks to physically get ready for the lead part. Besides visiting the infamous Charles Bronson in jail, he also rapidly gained 34 pounds.

Bronson was dissatisfied when he first met the English actor and remarked, "This kid would never be able to play me." After Tom bulked up, the offender said, "I honestly believe no one on the earth could play me as Tom did."

Jared Leto: Chapter 27

We saw Jared Leto’s weight loss transformation earlier, but he has also put on tons of weight for a role. Leto added 67 pounds to his lean body to more accurately portray John Lennon's killer, Mark David Chapman, in the movie Chapter 27. He could no longer walk to the site by the time filming was finished due to the additional weight.

Leto developed gout and was prescribed Lipitor due to his abrupt weight gain. However, according to Leto, understanding Chapman required putting on his skin.

Charlize Theron: Monster

This film character proved to fans that Theron was much more than just a lovely face. Charlize Theron's 30-pound weight gain for Aileen Wuornos, the real-life serial murderer, demonstrated her dedication to the part and her status as a Hollywood actor.

Donuts and potato chips made up most of Charlize Theron's diet for her role in Monster, allowing her to gain the 30 pounds she needed. In addition, Charlize colored her hair, removed her eyebrows, donned contacts and artificial teeth, and used skin-staining makeup.

Demi Moore: G.I. Jane

For the film G.I. Jane, Demi Moore took on the role of Lieutenant Jordan O'Neil, the first female Navy SEAL. Moore used a rigorous diet and workout regimen that included martial arts, strength training, and proper Navy SEAL training to transform herself into O'Neil.

Moore would begin her training for G.I. Jane at 4:00 am to complete it before filming began. She ran in Central Park while being followed by numerous security officers. She shaved her head, participated in Navy SEAL obstacle courses, and engaged in additional military-style training to fully inhabit the part.

Tom Hanks: Cast Away

For the role, the actor had to gain 50 pounds during pre-production to portray himself as middle-aged. They shot the scenes before the island sequences while Hanks was in this condition, and then they took a year off to allow Tom to drop weight to portray a castaway realistically. With a strict diet and workout routine, he lost 55 lbs in four months. He also grew out his hair.

His primary food sources were crab, fish, veggies, a small amount of fruit-based sugar, coconut milk, and water. The Castaway Diet is the name given to this diet in later years.

Edward Norton: American History X

Edward Norton was little more than a reliable performer with a horrible haircut and a scant number of good movies to his credit. Then he burst onto the screen as Derek Vinyard, a raving skinhead, and neo-Nazi with a physique that would make most men run for cover. Norton developed the sculpted chest and cut biceps of a standard Hollywood leading guy.

He gained 30 pounds of muscle from exercises that increased strength and a high-protein diet, giving him a lean, mean appearance that was ideal for his gruff part in American History X.

50 Cent: All Things Fall Apart

We're used to watching Curtis Jackson, aka 50 Cent, bulk up and rule the stage. To play a football player diagnosed with cancer in the movie All Things Fall Apart, the Queens rapper lost close to 60 pounds. Fitty, who typically weighs 214 pounds, posted a photo of himself at a sickly 160 pounds.

The rapper claims that he exercised for three hours each day on the treadmill for nine weeks while adhering to a liquid diet. His childhood friend, who passed away from cancer, served as an inspiration to him.

Robert De Niro: Raging Bull

DeNiro took it upon himself to depict decades of wear through his physical appearance when he portrayed Jake LaMotta, an Italian-American middleweight boxer whose self-destructive conduct was recorded over several decades. The celebrity put on 60 pounds, underwent intense training, and participated in Brooklyn boxing contests.

The filming was postponed for many weeks as De Niro traveled to Italy and consumed as much pasta as he could. Nevertheless, de Niro's commitment to the part gained him significant recognition in the movie business and raised the bar for all performers playing pivotal roles ever since.

Vincent D’Onofrio: Full Metal Jacket

Vincent D'Onofrio was a trim, attractive athlete who turned women's heads before being cast in Full Metal Jacket. D'Onofrio was forced to gain about 70 pounds and shave his head, a physical transition that had a startling effect. The marine recruit who acts as the emotional fulcrum for the movie's beginning is a fat, incompetent, and progressively troubled character.

Vincent D'Onofrio, who played a role in the film Adventures in Babysitting that same year, was profoundly impacted by how people treated him differently when he was heavier, saying, "it altered my life."

Michael Fassbender: Hunger

Michael Fassbender underwent a 42-pound weight loss to appear in the film Hunger. His character, Bobby Sands, died after 66 days during a 1981 hunger strike. Off-screen, Fassbender undertook a fast of his own to embody Bobby’s character, physically and emotionally.

His final weight was estimated to be 127 pounds. Theoretically, Fassbender was shedding pounds as advised: by cutting back on calories and working out. However, the picture above reveals that he went a little overboard.

Christian Bale: American Hustle

To give New York con man Irving Rosenfeld's elaborate comb-over more life in American Hustle, Christian Bale put on 42 pounds and had a portion of his head shaved. Bale's decision to adopt a slouched posture for his character even caused him to herniate a disc in his back, which reduced his height by three inches.

Although Bale famously shed more than 60 pounds for his role in The Machinist, American Hustle was by far his most notable physical change.

Anne Hathaway: Les Misérables

Anne Hathaway had her head shaved to portray Fantine in the Les Misérables movie adaptation. Before filming started, the actress underwent a strict cleanse that helped her lose 10 pounds. She then shed another 15 pounds by restricting her diet to two little squares of dry oatmeal paste daily.

Hathaway found it quite challenging to get in shape for the role. “First, I had to be fascinated with it since the goal was to appear dead, and I was in such physical and emotional squalor,” the actor remembered.

Daniel Radcliffe: Jungle

Although we are best familiar with Daniel Radcliffe as the bespectacled Harry Potter, he also plays other characters. The actor portrayed Yossi Ghinsberg, an Israeli explorer who was lost for three weeks in 1981 in an unexplored area of Bolivia's Amazon jungle.

To survive, he foraged for fruit and eggs from nests, losing 35 pounds as disease, infection, and starvation took their toll. Radcliffe has denied that he starved himself for two months to prepare, but his meager diet didn't include much variety.

Matthew Fox: Alex Cross

To play the emaciated antagonist in the action thriller Alex Cross, Fox lost about a fifth of his body weight. However, Fox was determined to accomplish it in a way that would leave him with enough focus to work hard, think clearly, and be a functioning husband and parent.

In other words, although his fat-zapping methods produced terrific outcomes, they didn't use strange techniques. Instead, he followed a strict yet nutritionally balanced diet, trained hard, and watched as his physique gradually transformed into nothing but lean, firm muscle.

Rooney Mara: The Girl with the Dragon Tattoo

Rooney Mara is descended from two affluent Irish-American families. The Girl With the Dragon Tattoo, in which she played the title role, served as the star's breakout performance. Rooney shed a lot of pounds and added a lot of piercings for the part of hacker Lisbeth Salander. She worked hard to get into this character.

The lead actress was given the role without the director David Fincher's insistence that she drop weight. However, she believed the character would be skeletal. Rooney also chose to keep a few piercings in case of a sequel!

Kit Harington: Pompeii

English actor Kit Harington had to gain weight for his role in the romantic historical disaster film Pompeii. However, while preparing for this role, Harington battled body dysmorphia, a compulsive concern with one's physical appearance. As a result, he developed an extreme obsession with going to the gym three times every day.

He experienced "exhaustion," and eventually, his trainer intervened to control him. In response to a question regarding the experience, the actor stated, "that was one of those experiences that I had never actually done before." One time will do!

Emma Stone: Battle of the Sexes

Emma Stone had to get in shape before taking on the role of former No. 1 tennis player Billie Jean King. To inhabit the athlete's muscular form, she also needed to put on a little weight. So, what is the most effective approach to attaining this? According to Stone, it’s protein shakes.

Jason Walsh, Emma's personal trainer, advised increasing the calories and fat Emma consumed to fine-tune her diet. Before the film, Emma was not physically suited to be a tennis player or a professional athlete. Therefore, packing on pounds of muscle was necessary for the Billie Jean look.

Hilary Swank: Million Dollar Baby

For her performance in Million Dollar Baby, actress Hilary Swank earned the Best Actress award in 2005. She portrayed fighter Maggie Fitzgerald, who was an underdog. Hilary Swank had to transform her body to look like someone who had likely spent her entire life working out as a boxer. This required more than just learning how to fight.

Swank had roughly 90 days to get in shape. Hilary invested 2.5 hours into boxing and 2 hours into weightlifting to complete this challenge. She exercised like this six days per week and added 19 pounds of muscle in two months.

Will Smith: Ali

Will Smith, being a slim guy, had to gain 35 pounds of muscle to portray the role of Muhammad Ali and faithfully resemble a heavyweight boxer. The announcement that slender Will Smith would play the powerful Ali sparked skepticism among some.

In the end, Smith proved them wrong. The celebrity exercised six hours a day, five days a week. In addition, he performed a lot of endurance training, which entailed lifting a lot of weights and running in boots through the snow. By the time filming began, Smith's bench press had reached 365 pounds.

Joaquin Phoenix: Joker

Everyone believed it would be impossible for anyone new to perfectly embody the Joker, but Joaquin Phoenix astonished everyone when he accepted the character. He underwent a tremendous transformation for the film, which enabled him to access the emotions required to play such a tormented character.

Joaquin Phoenix shed 52 pounds and nearly went insane for Joker. The Academy Award-winning actor claims that although he was aware that he needed to appear "hungry and unwell," he temporarily went "crazy" after becoming one of cinema's most recognizable villains.

Renee Zellweger: Bridget Jones’s Diary

Renee Zellweger has expertise in "becoming the role." The American actress decided to put on more than 30 pounds for the role of Bridget Jones in addition to perfecting her British accent. Despite increasing from a size 4 to a size 14, many people felt her size still didn't feel suitable for the role.

What transpired after filming ended adds to the dramatic nature of this shift. For the lead role in Chicago, Zellweger had to quickly lose all of the weight she had gained for her role as Bridgette Jones, and then some.

Eddie Redmayne: The Danish Girl

Eddie Redmayne, an English actor, received an Oscar nomination for his performance in The Danish Girl. Redmayne created the transgender artist from the inside out. In the end, Redmayne spent three years getting ready for the part, speaking with transgender people for hours, and reading Man Into Woman, the landmark biography of Elbe's life that was first published in 1933.

Lana Wachowski, who oversaw his performance in the movie, also gave him some guidance. Wachowski recommended reading Conundrum, a 1974 memoir by trans author Jan Morris.

Marlon Brando: The Godfather

Marlon Brando was one of the first performers to popularize method acting, long before Jared Leto or Christian Bale. The actor consented to take a test for Francis Ford Coppola's The Godfather after experiencing a bit of a career lull in the 1960s. It is now regarded as his finest achievement.

Marlon Brando adopted several gangster-inspired looks. To do so, he did such things as losing weight, stuffing his cheeks with cotton, donning a mouthpiece, and spending hours in the makeup department. He received his second Oscar for his efforts in The Godfather, but he declined it.

Lady Gaga: House of Gucci

Most people are accustomed to seeing pop sensation Lady Gaga wearing an outrageous costume, tall heels, and bright blonde hair. However, Lady Gaga lost herself in the role of Patrizia Reggiani in 2021's House of Gucci, exploring the character both on and off the screen. Gaga, real name Stefani Germanotta, excels in this part as a brunette powerhouse with an Italian accent.

Lady Gaga studied Patrizia's voice and worked with a dialect coach to prepare for the role. She also thought about what her friend Tony Bennett had said about the portrayal of Italians in the media.

Kumail Nanjiani: The Eternals

Kumail Nanjiani is a Pakistani-American actor and comedian who initially gained notoriety for his role as a geeky computer programmer. But as soon as he was cast in Marvel's The Eternals, he quickly transitioned from nerd to jock.

For his superhero role in The Eternals, the actor undoubtedly stepped up and put in the effort. When he revealed his makeover on Instagram, it was evident that he had worked very hard and endured "real physical pain" for a whole year to attain his new appearance for the movie.

Colin Farrell: The Batman

Colin Farrell nailed his portrayal of The Penguin in The Batman movie. However, the actor opted to wear a fat suit instead of gaining weight for this job. This is because he’d endured health problems while gaining weight for another role.

Farrell's initial makeup test required roughly 12 people and took about six hours. This included someone to do the hair, the teeth, the ears, additional people to do the makeup, and finally, a team to handle the bodysuit. We can certainly understand why everyone says he’s unrecognizable in the role. 

Charlize Theron: Bombshell

Charlize Theron is another performer who has experimented with playing real-life people. The actress donned prosthetics to become Fox News analyst Megyn Kelly in the dark comedy Bombshell from 2019.

Theron wore makeup to change the way her face looked in addition to wearing prosthetics and colored contacts. To complete the appearance, Theron added artificial eyelashes and a lot of anchor-style makeup. All the work paid off as she was nominated for a Best Actress Oscar. Unfortunately, she was unsuccessful. On the bright side, the team did win the prize for best hair and makeup.

Nicole Kidman: The Hours

In the 2002 film The Hours, Nicole Kidman played writer Virginia Woolf. The actor's prosthetic nose entirely concealed her identity when paired with the mousy brown wig. If you look closely at the movie, you'll notice that her eyes also have a noticeable droop, suggesting that the makeup experts worked far more magic than a nose and wig alone.

Nicole Kidman, whose red hair we all know and love, was hardly recognizable. For this transformation and her work and talent in this film, Kidman received the Best Actress Academy Award. Bravo!

Steve Carell: Foxcatcher

How drastically a prosthetic nose can alter a person's appearance is astonishing. Carell underwent a total makeover to play the insane philanthropist John du Pont, and the outcome was nothing short of spectacular. Carell spent almost three hours a day applying makeup for the 2014 film Foxcatcher.

Steve Carell recalls, "My look was so repulsive that nobody wanted to be around me, so I didn't get to know Channing or Mark." Nevertheless, it must have worked since the following year, Steve was nominated for the Best Actor Oscar.

Jim Carrey: The Grinch

How the Grinch Stole Christmas by Dr. Seuss is a well-known Christmas story that teaches gratitude and family values throughout the holiday season. These same ideas are upheld in the live-action version of the same movie, which also benefits from Jim Carrey's comedic ability to make the Grinch come to life in entertaining new ways.

Jim Carrey became so enraged during the nearly eight hours it took to apply the green character's makeup that he punched a hole in the wall of his trailer. A green outfit made of yak hair was also required for the celebrity. We’re glad he persevered! 

John Travolta: Hairspray

John Travolta's portrayal of a woman in the 2007 film Hairspray was one of the most impressive makeovers. Travolta portrayed Edna Turnblad, Tracy Turnblad's mother. Travolta's selection was the first time a straight male was picked to play Edna.

The well-known actor donned quite a few prosthetics for this delicious part. Due to Edna's provocative clothing choices, John Travolta wore prosthetics on his arms, head, neck, and legs. He also had to wear a bodysuit made of foam and spandex.

Jennifer Aniston: Cake

While this next makeover didn’t entail artificial limbs or drastic weight loss, it's still quite startling. In the movie, Aniston plays Claire Simmons, a drug-addicted woman obsessed with a fellow support group member who committed suicide.

Jennifer Aniston is accustomed to strolling the red carpet and looking flawless. However, the performer put on some weight and opted out of makeup for the 2014 thriller Cake. She admitted, “I stopped working out for two and a half months. I stopped exercising and eating as carefully as I usually do. I would allow more even though I was still healthy.”

Glenn Close: Albert Nobbs

Check out the drama Albert Nobbs, which stars Glenn Close as the title character. Once more, a cisgender actor was chosen to portray a trans man. There are enough trans performers to fill these roles, so we hope they’re given opportunities like this in the future.

Still, it's interesting to note that Glenn Close created this part for the stage and fought for 15 years to see it become a film. So, of course, she deserves ample respect. Glenn portrayed Albert, a butler who was born as a woman but lives as a man, in this 2011 film. She wore a short wig and prosthetics to embody the part.