Jared Leto at the 'Dallas Buyers Club' Premiere at the 2013 Toronto International Film FestivalJason Merritt/Getty Images

Currently stirring up awards buzz at this year's Toronto Film Festival, "Dallas Buyers Club" required more of its stars than just stellar performances. Matthew McConaughey and Jared Leto both had to drop significant amounts of weight to portray individuals who develop AIDS in the true-life story of their characters' struggle to make treatments more readily available.

For his part, Leto got down to 114 pounds for the role of Rayon, an HIV-positive transgender woman who helps McConaughey's Ron Woodroof smuggle in and sell alternative (read: non-FDA-approved) drugs from Mexico.

Jared Leto and Matthew McConaughey in 'Dallas Buyers Club'Focus Features

"I stopped eating," Leto told TheWrap at the after-party for the film in Toronto, revealing that he lost around 40 pounds. "After a while I stopped counting."

"It changes the way you walk, the way you sit, the way you think," he said.

It wasn't the first time Leto, who's now better known as the frontman for Thirty Seconds to Mars, had transformed his body for a movie: The actor packed on 67 pounds to play John Lennon's assassin Mark David Chapman in the 2007 thriller "Chapter 27," and he starved himself to play a drug addict in 2000's "Requiem for a Dream."

"Dallas Buyers Club," Leto's first film in five years, hits theaters November 1.

[via TheWrap]
Matthew McConaughey on His Weight Loss for The Dallas Buyers Club