The South African actress says that, as a child, she used to swim in the same waters where surfer Mick Fanning was attacked by a shark on Monday during a televised surfing competition in Jeffreys Bay.
Fortunately for Theron, 39, there was always someone with a whistle to warn beach-goers to quickly return to shore.
"You would come out and watch [the sharks] swim by," she said, speaking at the Los Angeles premiere of her upcoming movie Dark Places, sponsored by Apothic Wines and Svedka. "I never had anything by my feet ... Maybe they were, I don't know," she added with a laugh.
Watch: What It's like to Take a Selfie with a Shark
Looking back on the experience, Theron, who is now a mom to son Jackson, 3, finds the whole experience rather unnerving.
"It was just weird, because I saw that [Fanning's attack], and it was like a memory came back to me, and I went, 'Oh my God… Now that I'm an adult, now that I have my own kid, I'm just like, 'What were my parents thinking?' "
Theron says her parents were quite casual about it. "They were like, 'Oh, it's okay, just go and have fun at the beach!' "
Good thing she heard that whistle!
Dark Places hits theaters on Aug. 7.