22 Unbelievable (and Crazy) Movie Transformations (PHOTOS)

Charlize Theron is gorgeous, right? But not when she played serial killer/former prostitute Aileen Wuornos in the 2003 drama Monster. To mask her natural beauty for the role, Charlize gained 30 pounds and hid behind splotchy makeup and prosthetic teeth.

She explained to SPLICEDwire, “It wasn't about getting fat. Aileen wasn't fat. Aileen carried scars on her body from her lifestyle, and if I'd gone to make this movie with my body — physically I'm very athletic — I don't know that I would have felt the things Aileen felt with her body.”

Playing homely certainly paid off: Charlize took home the Best Actress Oscar for her work. And she was back to her svelte self in time to film 2004’s Head in the Clouds.