It's a wonder she still got the role after this one.
"It was not good," Theron exclaimed to Stephen Colbert on "The Late Show" Thursday night.
"I don't know why he gave me the role, I mean, honestly. I was so nervous," she continued. "Imagine you're 19 and you meet this idol. I idolized him! I watched 'Turner and Hooch' like 500 times. So to audition for somebody like that, it's frightening."
Being a die-hard Hanks fan made her so nervous she wasn't able to speak the lines correctly. "The character who plays my boyfriend in the movie, his character name was Guy," Theron recalled. "I had to do this scene, and Tom [Hanks] read with me. It's so mortifying. I got so nervous that I couldn't say Guy and I kept saying 'gay' and the more I tried to correct myself, the more I just said 'gay.'"
"It was just so horrible," the "Tully" star continued. "He literally said at one point, 'You know, let's just take a break. We'll come back.' And I was like, 'Ugh, I am sucking right now!'" Obviously she couldn't of sucked too badly, as Theron still booked the role.
Another discovery that Colbert learned about his guest: She never planned on being an actress. Theron explained that she was a professional dancer and that was always what she thought she was going to do.
"That was my passion, yeah, for sure. I thought that was what I was going to do for the rest of my life," the "Atomic Blonde" star said. "I'm not really built to be a ballerina. I'm a little too tall and too much weight on my knees. At 19 my body just kind of said, 'No more.' So I said, 'Movies!'"
Obviously choosing a career in acting really paid off for the now Oscar-winner. Her new film "Tully," which follows her character Margo, a mother of three, and the ups and downs of motherhood, has already received rave reviews, with a 90% on Rotten Tomatoes.
"Tully" opens everywhere Friday.