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?