In an interview to BBC Radio1 the "Brokeback Mountain" actor revealed that he would happily pile on the pounds for a part.
"I mean I think, it just depends on the role and it depends on if I am driven by it. I like to learn and do almost anything for a role. It is not an easy thing that, but I would give it a go," he said.
The 34-year-old actor who has always worked hard on the physical appearance of his character spent months in physical training and on a strict diet in order to get fit for his part as champion boxer Billy 'The Great' Hope in forthcoming movie "Southpaw".