2. Matt Damon
Although, he is not the typical method actor, yet Matt Damon has been able to surprise the audience with his incredible body transformations. His character for the movie Courage Under Fire required Matt to appear emaciated and sickly, for which he lost an impressive 40 lbs, risking his health in a dangerous way. He had to consume specialized medications for 18 months after the filming to get the adrenal gland fixed. And on the other hand, check out these roles:
Matt had to pile on 30 lbs (of fat) to portray his role in the movie Informant. He also grew a moustache and had his hair color changed to fit into this role. Then he revealed his perfect physique in the movie Elysium where he added 30 lbs of muscle mass. Additionally, Matt had his head shaved and tattoos etched on his body. Now we know why Matt is one of the highest paid actors in Hollywood.