It’s no secret that some actors go to extremes when gearing up for a role — whether it be losing weight, gaining weight or dying their hair to accurately portray a character. Other times, it’s the makeup artists who take things to another level, completely transforming a celebrity’s face in order to make a fictional or nonfictional person a reality onscreen.
From Charlize Theron’s transformation in “Monster” to Robin Williams’ “Mrs Doubtfire” look, here are 19 stars whose film personas will make you do a double-take: