Ashton Kutcher was Mila Kunis' first kiss.

The former 'That 70s Show' stars, who first met when the actress was just 14, started dating approximately 20 months ago following Ashton's split from Demi Moore, and their ex co-star Laura Prepon isn't surprised they're now madly in love.

The 33-year-old actress told UsMagazine.com at a Pre-Emmy Party in Beverly Hills, California, on Friday night (20.09.13): ''It's incredible! I wasn't surprised either.''

Laura insisted the couple's relationship is the real deal and confirmed that the 'Two And A Half Men' star was Mila's first kiss.

She said: ''He was. He was.''

The 'Orange Is The New Black' star worked with Ashton, 35, and Mila, 30, on the comedy series from 1998 until 2006 and revealed the entire cast is still close.

She said: ''They're like my family.''

It was recently reported that Ashton and Mila are engaged even though his divorce from Demi has not yet been finalised, and Laura expects an invite if and when they do tie the knot.

She said: ''Obviously if people wanted us there, which she would because we're all family -- then of course I would be there. We support each other no matter what.''