Ashton Kutcher used to do Mila Kunis' "chemistry homework" for her.
Mila Kunis and Ashton Kutcher
The 39-year-old actor is now married to the 'Family Guy' star - with whom he has two-year-old daughter Wyatt and six-month-old son Dimitri - but says when they met 20 years ago whilst filming 'That 70s Show', the pair were more like brother and sister on set.
Ashton revealed: "We've known each other for 20 years. I was 19, she was like 14. I did her chemistry homework for her. I think I was her first kiss, like, on the show. We have our first kiss memorialised on a TV show!
"It was really weird. I was like, 'Isn't this illegal?' I don't know, and it was really awkward, because I'm like a 19-year-old kid. She was 14! She was like my little sister. I wanted to make sure she was OK."
And the 'Jobs' actor also spilled that 33-year-old Mila used to keep a diary in which she branded the Hollywood hunk as "hot", before realising he was "annoying".
During an appearance on SiriusXM, host Howard Stern said of Mila: "She said she didn't think you were particularly good looking when she was 14."
To which Ashton replied: "She's lying! She has like, a journal or like, a diary from when she was a kid where she wrote, 'Oh, this guy's hot.' She thought I was cute!
"At first I think she thought that I was good looking, and then shortly thereafter, I was just annoying to her, because I was like a big brother. It was like, 'He's annoying, because he's always looking out for my best interest."
Meanwhile, Ashton recently paid tribute to his family when he picked up the Robert D. Ray Pillar of Character Award in April.
He said: "When I had these kids, my wife and I had these kids and we got to share that amazing, amazing, amazing honour, my first response was, I wanted to call my parents and say, 'I'm sorry, because I never knew how much you loved me."
Tagged in Ashton Kutcher Mila Kunis