Laura Prepon revealed to Us Weekly at the Variety Pre-Emmy Party on Friday, Sept. 20 that Ashton Kutcher was Mila Kunis' first kiss Credit: Gregg DeGuire/WireImage

Laura Prepon isn't surprised at all by Ashton Kutcher and Mila Kunis' relationship! The 33-year-old actress revealed to Us Weekly that her former That '70s Show costars, dating for over a year, are the real deal.

"It's incredible!" she told Us at the Variety & Women in Film's Pre-Emmy Celebration presented by Yoplait Greek in Beverly Hills, Calif., on Friday, Sept. 20. "I wasn’t surprised either," she said of the couple's budding romance.

The three actors all starred on the comedy for eight seasons from 1998 to 2006, and have stayed close since its finale. "They're like my family," she said. The friends are so close that the Orange is the New Black actress also revealed that Kutcher, 35, was indeed Kunis' first kiss. "He was. He was," she confirmed. Kutcher and Kunis' characters, Michael Kelso and Jackie Burkhart, dated on the show.

Together since April 2012, the Oz the Great and Powerful actress, 30, recently caused quite a stir when she stepped out with a possible engagement ring in L.A. in early September. Though no wedding bells yet, Prepon believes she would definitely get an invite. "Obviously if people wanted us there, which she would because we're all family -- then of course I would be there," she said. "We support each other no matter what."

As for the redheaded beauty, she's excited for season two of her Netflix hit, even though it's been previously reported that she will only be appearing in a few episodes. "It's an amazing show, and my character is a total badass," she said of OITNB. "I don't want to stop playing her because she is amazing, but I'm definitely coming back for season two, and it's going to be awesome." 

She added: "The fan support for my character has just been above and beyond what we expected and it's so appreciated."