Actress Charlize Theron attends the World Premiere of 'Prometheus' at Empire Leicester Square on May 31, 2012 in London, England. Credit: Dave M. Benett/Getty Images

Charlize Theron is no longer for sale.

During an appearance on TBS' Conan Tuesday, the star of Snow White and the Huntsman and Prometheus regaled host Conan O'Brien, 49, with a story about being auctioned off on a blind date for charity.

"Do not do it. It's like the worst idea ever," Theron, 36, warned the redheaded comic. "It's one of things where I was like, 'Yeah, I am a dumb blonde.' Who does that?"

Theron continued: "They trick you with the 'people are suffering' thing.  They trick you with the 'you can help so many people,' and you fall for it. And before you know it, you're at a restaurant with some stranger. Like, you could end up in [sex offender and serial killer Jeffrey Dahmer's] apartment that way! That's not a good idea."

The unattached Oscar winner -- mom to son Jackson, 6 months -- mustered up the courage to follow through on her promise and "go to dinner with this strange man." Because she still felt uneasy about it, she "made two girlfriends sit at the restaurant" nearby.

"The closer I got, I thought: 'This could actually turn out really bad,'" Theron recalled. "Rich people can be creeps, too! They can rape."

"Look, I would rather just give the money [to charity]," the South African star said. "It was a scary thing. And [the guy] was weird!"

The two never saw each other again, and Theron has not been in a serious relationship since ending her nine-year partnership with Stuart Townsend in 2010.