Ian Somerhalder lost his virginity at the age of 13.
The 40-year-old actor - who now has two-year-old daughter Bodhi with wife Nikki Reed - has spilled the details of the first sexual encounter he had with a woman who was 16.
Speaking to Andy Cohen on his SiriusXM show 'Radio Andy', Ian admitted: "It was fun."
Andy then asked: "Was that when your sexual life started?"
To which he replied: "When you're 13 and you're a boy ... boys are pretty on it."
The 'Vampire Diaries' alum also confessed that he used to spy on his older brother, who is seven years old than him, when he had women in his bedroom and that he learnt "a lot" about pursuing girls from his "Casanova" sibling.
He said: "He taught me a lot, and he was quite a Casanova.
"He used to have girls in his bedroom all the time and what I did was, I went into the bottom corner of his window and I pinched the Venetian blinds. I pinched the blinds down so I'd have a clear view.
"I'd go outside and I'd watch, and I learned a lot."
The father-of-one also admitted that he thinks it's "vastly unfair" that boys and girls are treated differently by their parents when it comes to them explaining sex and relationships.
He said: "It so vastly unfair.
"All my friends who are guys who have sons are like, 'Yeah, you're going to get a date, yeah,' while all the dads with daughters are like, 'I will kill these little bastards.' It's so vastly unfair."
Meanwhile, Ian recently hailed parents as "superheroes".
The former 'Lost' star is used to playing supernatural creatures on television, but said in his latest role as Luther Swan on Netflix show 'V Wars', he's playing a real "hero", because his character is a scientist and a parent.
He said: "I wanted to play a guy whose superpower was just being a good dad. He's a dad, he's a husband, he's a doctor. Literally, that's the guy's superpower.
"To me, scientists are superheroes. Great parents are superheroes. I am a parent now. I do recognise that it takes being a bit of a superhero to be a good parent, and that's all I wanted to play - just this guy. What we realised was people don't want an ordinary hero. They want an extraordinary hero. We retooled this entire trajectory of this guy."
Tagged in Nikki Reed Ian Somerhalder