The Young Adult star recalled the casting process for her first film 2 Days in the Valley in a new interview forW Magazine's February issue.
"I remember I was in a catsuit. I had never auditioned before, and I almost brought a bottle of ketchup and squirted it all over myself for the scene where I got shot," Theron explained.
"I looked like a maniac. It was a dying scene, so I barged through the door and started crawling on the floor. I think they were too scared not to give me the role."
Theron recently suggested that playing an ex-high school 'mean girl' in Young Adult may have been the most important role of her career.
The film's director Jason Reitman recently revealed that he would not have made Young Adult without Theron.
Watch a trailer for Young Adult below: