Matthew Fox lost his virginity aged 12.
The 'Lost' actor says his first sexual experience was "terrible and awkward" but he still remembers it in clear detail.
He explained: "I was 12. She was about two years older than me. It wasn't her first time.
"I can actually see the event in my mind's eye, like photographs. It was in Dubois, Wyoming, where the population sign probably says, to this day, about 1,000.
"It happened literally on the ground by a river while a rodeo was going on in town. It was absolutely terrible and awkward - just two f***ing kids lying down and pulling our pants down."
The 43-year-old star admits his sexual experiences improved as he got older, in particular when he was studying and playing American football at Columbia University.
He told Playboy magazine: "My sex escapades at Columbia were in my freshman year. That's what you're supposed to do. We didn't get any of the benefits of being football heroes. There was plenty of sex but no football-hero sex."
However, Matthew is now happily settled with wife Margherita - with who he has two children - though he admits he is an "appreciator" of women.
He added: "She's the love of my life. We have managed to both be intensely independent and maintain that strength in our relationship. I am a man, and I am an appreciator of women.
"At the same time, Margherita is the s**t. I can honestly say we're good together. We've been together for 23 years, so let's leave it at that."