The careers of Hollywood stars are full of physical demands and challenges. At times, just being talented is not enough, because certain roles may require the actor to look a certain way. In fact, one of the most challenging tests an actor can go through is undoubtedly playing a part that requires them to undergo some significant physical changes. Over the course of film history, several actors have drastically modified their physical appearance in order to perform certain roles. Whether by changing their weight, their hairstyle, or with the aid of makeup and prosthetics, many have achieved their goal of becoming unrecognizable on screen.

For example, this happened to Tom Hanks, who lost significant weight for his role in Cast Away, and to Lady Gaga, who changed her style, hair color, and speech for House of Gucci. Many of them achieved memorable roles, but those did not come without consequences: being exposed to such rapid changes in weight is detrimental to their health. Many have also been exposed to capillary and even eyesight issues due to prosthetics, contact lenses and modifications required for certain roles. Outside of the controversies related to this issue, there really are some actors who have amazed us with their roles, so here are 12 of the best actor transformations of all time.

Updated January 11, 2023: If you love films with epic actor transformations, you'll be happy to know we've updated this article with additional content and entries.

12 Brendan Fraser — The Whale

Brendan Fraser as Charlie in The Whale (2022)
A24

You've heard all about it by now. From acclaimed director Darren Aronofsky (mother!, Black Swan), The Whale stars Brendan Fraser (The Mummy, Crash) in an ultimate comeback role, and is based on a screenplay by Samuel D. Hunter, who adapted his 2012 play of the same name. The film also stars Sadie Sink (Stranger Things), Hong Chau (Watchmen, Homecoming), Ty Simpkins (Jurassic World), and Samantha Morton (Minority Report). It's now in theaters, and tells the story of an obese, reclusive English teacher who attempts to reconnect with his estranged teenage daughter. It's also fair to say this film is the talk of the cinematic town. Indeed, Fraser has already been nominated for several majors awards this season, and the Oscars are just around the corner. Although Fraser's character has been met with mixed reactions, there's no denying that the transformation is groundbreaking.

11 Jim Carrey — How The Grinch Stole Christmas

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Imagine Entertainment

The 2000 film directed by Ron Howard and inspired by the Dr. Seuss story is considered a Christmas classic. In How The Grinch Stole Christmas, Jim Carrey plays the Grinch, a bitter, grumpy character whose dream is to put an end to Christmas once and for all. What very few people know is that this movie, which won an Oscar for Best Makeup and Hairstyling, almost didn't make it. During the first make-up test, the team required eight and a half hours to transform Carrey into his character, and he was wearing so many layers of make-up, prosthetics and clothing that the actor felt as if he was being buried alive. He was so frustrated that he wanted to quit, so the production team hired a torture specialist to teach the actor distraction techniques so that he could endure the process (via Radio Times). Ultimately, the training paid off: Carrey managed to undergo the transformation more than a hundred times during the filming.

Related: Tom Hanks' Best Movie Transformations, Ranked

10 Brad Pitt — The Curious Case of Benjamin Button

the curious case of benjamin button
Paramount Pictures

This 2008 film tells the story of Benjamin Button (Brad Pitt), a man who was born with the body of a 90-year-old and grows younger as he ages. It was inspired by the story by F. Scott Fitzgerald and was directed by David Fincher. The curious thing about this movie is that it is made with excellent special effects: in fact, the first fifty minutes of the movie Benjamin Button's head is animated in CGI. Brad Pitt insisted on playing the character during the whole shoot and throughout all his life stages, which is why, in the elderly stages, the production made use of special effects to bring him to life as a realistic character. Of course, not all the film was computer-animated; makeup and hair extensions were also used to recreate the different phases of Benjamin's life. Ultimately, The Curious Case of Benjamin Button garnered numerous awards nominations and won more than 25 awards, including the Oscar for Best Visual Effects and Best Makeup and Hairstyling.

9 Robin Williams — Mrs. Doubtfire

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20th Century Fox

Daniel Hillard (Robin Williams) is very much what his children would consider a wonderful father, but his wife is tired of him acting like a child. After a divorce and losing custody of his three kids, Daniel decides to disguise himself as an old lady and work as a nanny at his ex-wife's house in order to spend more time with them. This new role not only allows him to share some time with the children, but also makes him a better father.

Mrs. Doubtfire was released in 1993 and was directed by Chris Columbus. In order to play the nanny, Robbie Williams had to undergo four and a half hours of makeup and hairstyling each day of filming during which the crew worked their magic, but they succeeded: the movie was a hit and the following year won the Oscar for Best Makeup and Hairstyling.

8 Nicole Kidman — The Hours

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Miramax Films

The Hours is a 2002 dramatic movie directed by Stephen Daldry and inspired by the novel by Michael Cunningham, which won the Pulitzer Prize in 1999. In it we follow the story of three women in different times and generations, whose lives are connected through Virginia Woolf's novel Mrs. Dalloway. Nicole Kidman plays Virginia Woolf in 1923, while writing Mrs. Dalloway. Julianne Moore is an unhappy wife reading the book in 1951, and Meryl Streep plays a New York publisher, a modern Mrs. Dalloway who cares for a writer friend, with whom she had an affair in her youth, in the advanced stages of AIDS and has decided to throw him a party. In this film, Kidman wore a prosthetic nose in order to play the writer Virgina Woolf, for which she received the Oscar for Best Actress.

7 Tom Cruise — Tropic Thunder

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DreamWorks Pictures

A team of actors shoots a movie about the Vietnam War. The director, unable to control them on set, decides to abandon them in the middle of the jungle and record them with automatic cameras. From then on, the performers must survive the real danger by appealing to their acting skills.

Tropic Thunder is a 2008 parody directed by and starring Ben Stiller, along with Robert Downey Jr. and Jack Black. Tom Cruise played Les Grossman, a Hollywood shark who refused to be trampled even by the rebels who had kidnapped the cast of his movie. The actor amazed the audience with this memorable and histrionic character, whose appearance and dancing were suggested by himself to have fun during the filming, and consisted of a bald head, several extra pounds, abundant hair on his body and even over-sized prosthetic hands.

6 Charlize Theron — Monster

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Newmarket Films

Monster is a gripping and touching 2003 thriller based on the real-life story of Aileen Wuornos, a sex worker executed in the fall of 2002 in Florida after she was convicted of murdering six men. Although Wuornos confessed to the six murders, including the murder of a police officer, she claimed to have killed only in self-defense, resisting violent attacks while working as a prostitute.

In the movie, directed by Patty Jenkins, Aileen is played by Charlize Theron in one of her most impressive acting transformations. To embody the character, the actress felt that she had to have a relationship of abandonment with her body, so she gained more than forty pounds and stopped taking care of her appearance. At the same time, she had her hair dyed and underwent dental prostheses. At the Academy Awards the year after the premiere, Theron won her first Oscar for Best Actress.

Related: Meryl Streep's Best Movie Transformations, Ranked

5 Matthew McConaughey — Dallas Buyers Club

Matthew McConaughey in Dallas Buyers Club (2013)
Focus Features

This 2013 biopic features a stellar cast led by Matthew McConaughey, joined by Jared Leto, Jennifer Garner, and Steve Zahn. Directed by Jean-Marc Vallée, Dallas Buyers Club is based on the life of Ron Woodroof (McConaughey), an electrician and cowboy by trade who is diagnosed with HIV. With a life expectancy of only 30 days, Ron is sent home with the sole help of a highly toxic drug. Faced with this situation, the man decides to head to Mexico and start smuggling a drug that is not approved by U.S. agencies. Soon, his popularity grows, and many other sick people come to him for help.

Ron was one of the great roles in McConaughey's career, for which he not only had to lose significant weight, but demonstrate a variety of nuances as an actor. His transformation and commitment to the film (Leto also had to undergo a transformation) paid off: the critics gave him their approval and in 2014 he won the Oscar for Best Actor.

4 Marion Cotillard — La Vie en Rose

Marion Cotillard La Vie en Rose 2007-legende
Légende Films

Marion Cotillard steps into the shoes of Edith Piaf in this autobiographical film about the legendary French singer that follows her childhood, hits, passions and low points. La Vie en Rose was directed by Olivier Dahan, and Cotillard had to completely shave her eyebrows and part of her hairline in order to resemble the singer completely, in addition to perfecting her singing technique with extended singing lessons and working on her accent. This role won her four Best Actress awards in 2008, including an Oscar. The film was well received by critics and also won a large number of awards.

3 Robert De Niro — Raging Bull

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United Artists

Raging Bull is a 1980 film directed by Martin Scorsese, based on the book Raging Bull: My Story by boxer Jake La Motta. It was nominated for eight Oscars and won two, Best Film Editing and Best Actor for Robert De Niro. In the movie, the actor performs the role of Jake La Motta, a young boxer who trains hard under the guidance of his brother and manager Joey in order to fulfill his dream of becoming a champion. However, Jake himself is very violent and paranoid, venting his aggression both in and out of the ring, and when he finally succeeds, his life turns into a nightmare. On one hand, his marriage gets worse due to his constant nights out with other women, and on the other hand, the mob puts pressure on him to fix fights.

De Niro was the first actor to carry out such an impressive transformation: he went from training hard to achieve the body shape of a boxer to putting on 65 pounds in a few weeks to play Jake La Motta in his overweight adulthood.

2 Christian Bale — Vice

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Plan B Entertainment

This actor is one of Hollywood's biggest chameleons. Among Christian Bale's most striking transformations was the role of Dick Cheney in Vice, a 2018 film that explores the true story of how Cheney, a quiet Washington bureaucrat, ended up becoming the most powerful man in the world as Vice President of the United States during George W. Bush's (Sam Rockwell) administration, with repercussions for his country and the rest of the world. To become the former ruler in Adam McKay's film, the actor shaved his head, gained 40 pounds and learned the politician's movements and gestures. That coupled with a great makeup and hairstyle team secured him the Oscar for Best Actor in 2019, among other awards.

1 Rooney Mara — The Girl with the Dragon Tattoo

mara-the-girl-with-the-dragon-tattoo-2011-columbia
Columbia Pictures

The books were fantastic, as were the Swedish film adaptations. Then came Rooney Mara’s second collaboration with David Fincher, which showcased some of her best work of all time. The Girl with the Dragon Tattoo, based on Stieg Larsson’s best-selling novel trilogy, further launched Mara into stardom with a stunning performance as the infamous Lisbeth Salander. The film follows Mikael (Daniel Craig), a disgraced journalist who teams up with Lisbeth to solve the disappearance of a billionaire’s niece. Mara stands out as the highlight of the film, to say the least — if only she'd continue starring in some sequels!