Jared Leto has admitted that losing lots of weight for movie roles is "a crazy thing to do".
The actor has previously gained and lost weight for parts in films like Requiem For A Dream and Chapter 27 and most recently shed more than 30 pounds to play a drug-addicted transsexual in Dallas Buyers Club.
"It's a tool. That's it," he said of the weight loss. "It's a crazy thing to do and incredibly stupid and dangerous.
"But it's a great tool because it changes how you walk, how you talk, how you sit, how you breathe, how you eat, how you laugh, how people treat you. It creates a sense of fragility."
The film, which stars Matthew McConaughey as an HIV positive man who smuggles medication into the US in the 80s, is garnering plenty of awards buzz and received a standing ovation when it premiered at the Toronto International Film Festival.
But Jared, who has spent the last five years out of the acting game while he concentrated on his band 30 Seconds To Mars, admitted he has not yet watched it. During the premiere he went back to his hotel to work on a music video.
"Based on the past 48 hours of the most effusive praise I've ever gotten, the film can never live up to any expectation that I would have for it," he said. "I'll give it a few decades."
The 41-year-old star was drawn to the role of Rayon in Dallas Buyers Club as soon as he read the script.
When he met with the director Jean-Marc Vallee via Skype, he was already getting into character.
"I used it as a test for myself," Jared said. "I got some lipstick. We said hello and then I reached over and grabbed the lipstick and I proceeded to put it on. He was kind of like, 'What the hell is going on?' I took off my jacket and I had a little pink sweater on."