● Comic-book fanboys were pissed when word got out that Chris Evans would be playing Captain America. To let the actor who had previously played Johnny Storm in both Fantastic Four films also grab Captain America’s fabled shield, they charged, was blasphemy. Settle down, guys. Evans took the role seriously—working with a personal trainer to build bigger biceps and tone his abs—and completely transformed his body, morphing from the leanness of the Human Torch to the jacked frame of Marvel Comics’ super soldier.
JEREMY RENNER The Contender, 40
● The California native flexed his acting muscle in The Hurt Locker and The Town (the one-two punch earned him back-to-back Academy Award nominations). Next he’ll be busting out the big guns in the upcoming Mission: Impossible sequel, Ghost Protocol. To prep for the role, Renner trained hard in the gym while developing a lethal arsenal of fighting techniques. “I’m doing hand-to-hand combat, Muay Thai, and kung fu and learning how to take someone out quickly,” he says. “I need to look like I know what I’m doing!”