Most of the time being a Hollywood actor is all about the glitz and the glamour, but occasionally actors have to go that extra mile to transform themselves for a role. Take a look at some of the most dramatic actor transformations ever seen on film.
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Warner Bros. Pictures
Clooney gained more than 30 pounds and grew a graying beard in hopes that audiences wouldn't instantly recognize him playing pudgy CIA operative Bob Barnes in 2005's "Syriana," a role that won him an Academy Award for Best Supporting Actor.