Some stars go to great lengths to get into character. Matthew McConaughey, Anne Hathaway, Renee Zellweger, and Christian Bale are just a few of the many celebrities who've lost or gained significant amounts of weight for movies
Jared Leto in Chapter 27/Dallas Buyers Club
Leto famously gained weight to play Mark David Chapman in 2007's Chapter 27. Five years later, he went in the opposite direction, shedding 30 to 40 pounds to play an HIV-positive transsexual in Dallas Buyer's Club. To get down to 114 pounds, he "stopped eating," he told The Wrap. "It changes the way you walk, the way you sit, the way you think."