Topher Grace finds Ashton Kutcher and Mila Kunis' marriage "fascinating."

Asked if there were ever signs the couple were meant to be together on the set, the 37-year-old actor told Andy Cohen on 'Watch What Happens Live': "It's funny, 'cause it's fascinating to everyone but it's fascinating to people in the cast, too. Because, no. I mean, we were all buddies, but...It's so great. It's like two of your best friends from high school, like, met years after high school and got together. It's so cool."

Mila, 32, and Ashton, 37, played high school sweethearts on the comedy and the brunette beauty, who landed the role of Jackie Burkhart when she was just 13, previously admitted her now-husband was her "first real kiss."

The 'Black Swan' star said: "My first real kiss ever was with him on the show. And when 'That '70s Show' had a prom, my date for the prom turned out to be my fiancé. We can honestly say that we went to prom together! Although I do think that in that episode I went home with someone else. We don't talk about that part."