13. Jared Leto lost 30 pounds and underwent a whole set of transformations, including having all his body hair and eyebrows waxed, for his role as Rayon in Dallas Buyer’s Club (2013).
In just around four months of time Jared Leto transformed himself into the transsexual AIDS patient he portrays in the movie. He went on a serious diet routine and removed his iconic beard as part of it. He also posted the progression of his transformation on Instagram. He also met transgender people to prepare for his role and it is said that he grounded the portrayal on these meetings. He spent all the time on set in character, so much that the director stated he doesn’t know Leto because “Jared never showed me Jared”.(source)
14. Renée Zellweger gained 20 pounds, learned English accent and worked undercover in a publishing firm in London to prepare for her role as Bridget Jones in Bridget Jones’s Diary (2001).
In the beginning many have expressed reservations about casting an American for a character that is British. However, when the film was finally released her south-eastern English accent was considered to be of high standard. Renée Zellweger received much critical acclaim and many awards for her role as Bridget Jones, including a nomination for the Academy Award for Best Actress.(1, 2)
15. For her role as Nina in Black Swan (2010), Natalie Portman trained for 8 hours a day as part of rehearsals and had to be on a diet of carrots and almonds.
According to the director Darren Aronofsky, it was Natalie Portman who had it worse when compared to the rest of the cast because of the kind of diet she had to be on. She lost 20 pounds during the course of training that lasted for six months. Though there have been many controversies, especially regarding the dance sequences, it is hard to deny that her portrayal of the good and the repressed dark sides of the character were just perfect.(1, 2)
16. Anne Hathaway had to lose 25 pounds to look like she is starving and nearing death as well as cut her long hair on camera for her role as Fantine in Les Misérable (2012).
The producers of Les Misérables didn’t want to audition Anne Hathaway in the beginning because she was too young for the role. But she persisted and went in to sing the song “I Dreamed a Dream”. The producers were astonished at her singing abilities and of course they had to cast her. Later she started on her strict diet regimen that sometimes consisted of thin squares of dried oatmeal paste.(source)
17. Adrien Brody lost 30 pounds, gave up his apartment, sold his car, disconnected his phones and moved to Europe for the role of Wladyslaw Szpilman in the movie The Pianist (2002).
Brody also read the memoirs of Szpilman to understand the “pain and horror of the Holocaust”. Szpilman had to scavenge for food while trying not to be spotted by the Nazis. Brody felt that he couldn’t’ have acted without knowing the emptiness and desperation one has when starving. He said that the sadness of being apart from the people and the things from his usual life had put him in the character. He also took piano and dialect lessons to play the character.(source)
18. Matt Damon went on an extreme diet regimen along with physical exercise to lose 40 pounds for his role in Courage Under Fire (1996). His health got so deteriorated that he had to be put under medical supervision.
At the time of filming Matt Damon was not a well-known actor. His regimen consisted of chicken breast, egg whites and one baked potato per day, with coffee, cigarettes and six and a half miles of running twice a day. It took almost two years for him to completely recuperate from the damage it did to his body. His dedication, however, managed to impress the movie’s director Francis Ford Coppola who gave him the main role in The Rainmaker. His performance also impressed Steven Spielberg who roped him in for Saving Private Ryan.(1, 2)