Mila Kunis' First Kiss: Ashton Kutcher, Says Laura Prepon

Mila Kunis shared her first kiss with Ashton Kutcher on the set of "That '70's Show," according to their co-star Laura Prepon.

Kunis was cast at age 16 as Jackie Burkhart, Kutcher's onscreen girlfriend on the sitcom, which ran from 1998 to 2006.

The cast, including Kutcher, Kunis, and Prepon all remained close since the finale of "That '70's Show."

"They're like my family," Prepon explained of her co-stars while at the Variety Pre-Emmys Party in Beverly Hills, Calif. on Friday.

"I wasn't surprised either," she added, according to Us Magazine.

Despite working closely together on the television series, Kutcher and Kunis only began dating last year. However, Prepon revealed that the late-budding relationship came as no surprise.

"It's incredible," Prepon said at the Variety Pre-Emmys Party in Beverly Hills, Calif. on Friday, according to Us Magazine. "I wasn't surprised either."

Prepon also said in a past interview that she believed Kutcher and Kunis are "totally going to marry" and revealed that she would be a bridesmaid.

"Of course will [be there], are you kidding me," the actress said while speaking to The New York Daily News in June. "All of us are going to be right up there on the altar."

Meanwhile, recent reports suggested that Kutcher and Kunis are already engaged. Although the reports were deemed false, the actors have been dating over a year and have intentions to marry in the future.

"They are not engaged," a source close to the couple told People magazine. "He knows what they have is amazing and special. He's been thinking about proposing for a long time."

In the meantime, Kutcher is still dissolving his six-year marriage to Demi Moore. The former spouses have not yet finalized their divorce despite having split up two years ago.

"They are desperate to get married as soon as possible because they want to start a family and are slightly old-fashioned about these things," another source said of Kunis and Kutcher, according to The Sun U.K.

As for the actors' professional lives, Kunis is experiencing a career high of late. The actress will appear in the upcoming films "Third Person," "The Angriest Man in Brooklyn," "Hell & Back," and "Jupiter Ascending."

Alternately, Kutcher is preparing to return to the set of "Two and a Half Men," for which he receives an estimated $750,000 per episode.