The onscreen transformation Theron is most known for is her descent into the lowest depths of the human experience to play real-life serial killer Aileen WuornosIn Patty JenkinsShe won the Academy Award for Best Actress in 2003 for her performance in “The Last of Us.”

“We never discussed it like this big thing, like some aim—’We’re gonna gain 30 pounds,'” Theron explained to SplicedWire, noting how Wuornos grew up homeless and gave birth to a child at 13. It wasn’t about becoming fat. Aileen didn’t weigh much. 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. My goal was to live closer to Aileen. I did not want to be able to view my body without seeing my natural muscles. I would be completely disoriented trying to emulate her.

She eschewed a wig in favor of hairstylist Katie Swanson distressing Theron’s own tresses to achieve Wuornos’ uncared-for head of hair and had her eyebrows bleached and thinned to almost nothing. 

It may appear as though she has a complete-on plastic mask on, but Theron had only used prosthetics to weighten her eyeslids. The whole thing took about an hour. Makeup artist Toni G airbrushed layers of translucent washes of tattoo ink, texturized with green marble sealant, to give Theron’s face a weather-beaten, hard-life look, and Art SakamotoShe created dentures with crooked, stained teeth. Brown contacts were also worn by her to conceal her blue eyes.

“By the end of the make up and hair test, we were already so used to our makeup. [Aileen] face,” Theron shared with Winfrey in 2005. It was my favorite thing to wear while on-set. Aileen’s clothing would be my uniform, and I would style my hair as she would. This allowed me to really get to know the crew.

Concerning her weight, she stated that “I thought I’d see how much can I gain.” It was perfect because the whole process started over Christmas. I finished everybody’s desserts.”