Matthew McConaughey lost almost a quarter of his own body weight for his role in 'Dallas Buyers Club' but he's not the first star to go to extreme lengths for the sake of an acting role.
Christian Bale also famously shed the pounds (and then some) for his portrayal of Trevor Reznik in 'The Machinist', whilst Renée Zellweger piled on the weight to play Bridget Jones.
But how many stars do you recognise following their drastic big screen body transformations?
Actor Transformations
Actor Transformations(01 of26)
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Actor Transformations(02 of26)
50 Cent looked unrecognisable as a cancer-stricken football player in 2011's 'All Things Fall Apart' thanks to a liquid diet and three hours a day on the treadmill. Shame all that effort went to waste when the film was universally panned upon release. (credit:Getty)
Actor Transformations(03 of26)
Actor Transformations(04 of26)
Cameron Diaz was more plain Jane than sun-kissed all-American gal for her role in 'Being John Malkovich'. (credit:AP)
Actor Transformations(05 of26)
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Actor Transformations(06 of26)
Not only did Charlize Theron gain weight for her Oscar-winning portrayal of serial killer Aileen Wuornos in 2003's 'Monster' but she also had her skin layered with tattoo ink to give her a weathered look, wore false teeth and had her hair thinned. (credit:AP)
Actor Transformations(07 of26)
Actor Transformations(08 of26)
Christian Bale lost 60lbs thanks to a diet of 'coffee and apples' for his role in 2004's 'The Machinist'. (credit:AP)
Actor Transformations(09 of26)
Actor Transformations(10 of26)
Jake Gyllenhaal shocked onlookers with his gaunt appearance at the 2013 Annual Hollywood Film Awards after losing 20lb to play a freelance crime reporter in his new film 'Nightcrawler'. (credit:PA)
Actor Transformations(11 of26)
Actor Transformations(12 of26)
As well as losing a huge 40lbs to play transgender AIDS activist Rayon in the 'Dallas Buyers Club' Jared Leto waxed off every bit of his body hair - including his eyebrows. (credit:PA)
Actor Transformations(13 of26)
Actor Transformations(14 of26)
'Dallas Buyers Club' wasn't the first time Jared Leto went on a drastic diet for a film role. But back in 2007 he piled the weight ON to play John Lennon's chubby assassin Mark Chapman in 'Chapter 27'. (credit:PA)
Actor Transformations(15 of26)
Actor Transformations(16 of26)
Tom Cruise as fat, balding Les Grossman in 'Tropic Thunder' really is a sight to behold. And fair play to the usually impeccably turned out and (let's face it) uber handsome star for agreeing to send himself up and look so nasty on screen. (credit:Film Magic)
Actor Transformations(17 of26)
Actor Transformations(18 of26)
The usually uber-glam Mariah Carey ditched the layers of slap and dyed her her brown to play dowdy welfare caseworker Ms. Weiss in 2009's 'Precious'. (credit:AP)
Actor Transformations(19 of26)
Actor Transformations(20 of26)
Matt Damon became so frail following a strict regime of food deprivation and physical training for his role in 'Courage Under Fire' that he was put on medical supervision for several months after he finished shooting the movie. (credit:PA)
Actor Transformations(21 of26)
Actor Transformations(22 of26)
After being fitted with a prosthetic nose for her lead role in 2002's 'The Hours', Nicole Kidman managed to go largely unnoticed by the paparazzi, which was handy as she was going through a divorce from Tom Cruise at the time. (credit:AP)
Actor Transformations(23 of26)
Actor Transformations(24 of26)
Renee Zellweger admitted she had 'panic attacks' when she discovered the health implications of putting on two stone in a short amount of time to fatten up for her lead role in the 'Bridget Jones' films (credit:AP)
Actor Transformations(25 of26)
Actor Transformations(26 of26)
Matthew McConaughey lost almost a quarter of his own body weight to play AIDS sufferer Ron Woodfroof in 'Dallas Buyers Club'. Despite admitting a loss of sex drive and occasional irritability while he was dieting, the actor also claimed the calorie restriction led to increased mental agility: “What I lost down there, I gained up here,” he said. (credit:PA)