Some actors play parts. Others become them. And the ones in the latter group are usually those whose performances are remembered for generations. When an actor dissolves into a character, a physical transformation is often in order—and these changes can either be subtle or taken to the extreme. To honor some of the most memorable body overhauls in silver screen history, we’ve created our very first Hollywood Fitness Hall of Fame. Find out who got inducted, and let their commitment compell you to make some Oscar-worthy changes of your own.