While CGI, prosthetics, and makeup can do wonders, some actors take transformation to the next level – pushing their bodies and minds to the limit through intense physical routines so they can fully embody their characters. Whether it’s packing on muscle, shedding dozens of pounds, or sticking to bizarre diets, these have to be some of the most extreme celebrity transformations we’ve ever seen.
From the acclaimed actor who gained 100 pounds between roles, to the beloved actress who survived on just one type of food during filming, these are some of the most jaw-dropping, commitment-fueled transformations in Hollywood history.
These transformations were achieved under professional supervision and for artistic purposes. Extreme dieting or rapid body changes can be harmful and should not be attempted without medical guidance.
Christian Bale as Trevor Reznik in "The Machinist", Batman in "Batman Begins"
Christian Bale – The Machinist (2004), Batman Begins (2005)
If there’s one thing Christian Bale is going to do, it’s commit to an extreme physical transformation for a role. The actor lost 63 pounds to play Trevor Reznik in The Machinist (2004), an emaciated insomniac. Reflecting on the experience, Christian told the BBC: “It just didn’t enter my head that it could be done any other way, really. I just realized, ‘Okay, I have to lose weight.’ I just had no idea how much I would have to lose in order to get the look that I was searching for.”
He then had to completely reverse it – and fast – for his role as Batman in Christopher Nolan’s Batman Begins (2005). The actor gained 100 pounds in five months for the role – going from 120 to 220 – and was reportedly just trying to get “as big as he possibly can”. You wouldn’t know there were just five months between those two appearances – and Christian’s extreme transformation has been deeply frowned upon by both heath professionals, and now the actor himself.
Speaking to the Sunday Times Culture magazine in 2019, Christian said: “I can’t keep doing it, I really can’t”, acknowledging the risks such extreme yo-yo dieting poses.
Charlize gained nearly 50 pounds for both "Monster" (top) and "Tully" (bottom)
Charlize Theron – Monster (2003), Tully (2018)
Charlize Theron gained weight for two different roles, and has spoken candidly about how one felt so different 15 years later. She gained nearly 50 pounds to play both serial killer Aileen Wuornos in Monster (2003) and a postpartum mother in Tully (2018), reportedly tucking into processed foods and takeaways.
“When I was 27, I did ‘Monster’. I lost 30 pounds, like, overnight. I missed three meals and I was back to my normal weight,” Charlize told Allure in 2023. “Then I did it at 43 for ‘Tully’, and I remember a year in trying to lose the weight…I called my doctor and he was like, ‘You’re over 40. Your metabolism is not what it was’”.
Matthew called the weight loss process "militant"
Matthew McConaughey – Dallas Buyers Club (2013)
Matthew McConaughey dropped down to just 135 pounds to convincingly portray Ron Woodroof, a stage four HIV patient, in Dallas Buyers Club (2013). At just under 50 pounds total weight loss, his strict diet was limited to egg whites, fish, vegetables, and tapioca pudding.
Though it was difficult, Matthew called it necessary for the role to truly embody the character, who is based on a real person. “It was my responsibility,” Matthew said during an appearance on The Joe Rogan Podcast in 2020. “I did not torture myself. I was militant”. The actor also told Graham Norton he's happy that people began to look past this once they saw the film – "Yes the weight loss was something, but you see who this guy was," he remarked.
The transformation was quite a physical contrast to his previous role in Magic Mike (2012).
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Tom had a very short amount of time to gain 35 pounds
Tom Hardy – Bronson (2008)
To play the titular criminal in Bronson (2008), Tom Hardy had to gain 35 pounds in 5 weeks – an average of 7 pounds every week – leading up to shooting. The goal wasn’t to gain muscle but weight, to authentically portray the real-life criminal’s hulking figure that was a key part of his violent and notorious image in prison. Instead of bulking up his portions, Tom instead had to put weight on more quickly.
“It was a race against the clock,” Tom told Ask Men in 2009. “I ate chicken and rice…Then I’d have a pizza, Haagen-Dazs, and Coca-Cola…I had to quickly put a lot of weight on my forearms, chest, and neck”. Tom certainly looked menacing in the film, and reportedly kept up a similar diet to play Bane in the Dark Knight series.
Robert described gaining the weight for "Raging Bull" as an "experiment"
Robert De Niro – Raging Bull (1980)
Raging Bull (1980) remains one of the most iconic sports films ever, and it’s one that acting legend Robert De Niro had to gain 60 pounds for. To authentically play real-life boxer Jake LaMotta in his later years, Robert went from training like crazy in the gym to intentionally gaining weight over a period of three months.
During a roundtable for The Hollywood Reporter, Robert shared that it was a conscious choice he made that director Martin Scorsese agreed to. The actor recalled seeing Jake LaMotta on the streets of New York, and remarked, “I thought the graphic difference of being out of shape and then being a young fighter was really interesting”. He described gaining the weight as an “experiment”, because he wanted to avoid prosthetics where possible. The actor went on to win an Oscar for the role.
Joaquin found losing weight for the second "Joker" film harder than the first
Joaquin Phoenix – Joker (2019)
If there’s one thing that will get you in the mindset of playing a supervillain, it’s eating a diet of lettuce and steamed vegetables. To play Arthur Fleck in Joker (2019), Joaquin Phoenix reportedly lost 52 pounds – under medical supervision to maintain his health – in order to achieve the character’s gaunt physique.
He later undertook the same diet for Joker: Folie à Deux (2024), but found it a lot more difficult. “This time it feels a bit more complicated just because there was so much dance rehearsal that we were doing,” Joaquin said during a press conference at the Venice film festival. “But I’m now 49, I probably shouldn’t do this again”. With no current plans for a third Joker flick, the actor’s in the clear for now.
Anne said it took "a really long time" to recover from her Fantine diet
Anne Hathaway – Les Misérables (2012)
For her role as Fantine in the film adaptation of Les Misérables (2012), Anne Hathaway had to lose 10 pounds before filming, and then a further 15 during as the character became increasingly unwell.
The Oscar-winning actress told People that she felt “very anxious and very lost at that time” due to the effect of the calorie restriction on her brain function and overall happiness. “It took a really long time to come back from it…and I was still really sick because of it”.