Despite continuing to deny rumors of a brewing romance, Ashton Kutcher and Mila Kunis have been spotted together again, this time on the set of Kutcher's CBS sitcom "Two and a Half Men."

The stars were photographed by a fan hanging out backstage after a taping of the show. The fan, who describes herself on Flickr as a friend of "Two and a Half Men" star Angus T. Jones, captioned the photo of her and Kunis saying, "I was so happy when I heard her and Ashton were together. They make such a cute couple! Looking forward to seeing her a lot on set this year!"

The couple, who are reportedly living and vacationing together, met back in 1998 on the set of "That 70's Show," where they played fictional couple Michael Kelso and Jackie Burkhart. Kutcher was 20 at the time that "That 70's Show" began taping, while Kunis had only just turned 15.

In the past few months Kunis has addressed the rumors that the two are dating, calling them "absurd," and defending the relationship as purely platonic. "Listen, we hang out. We've known each other for 15 years," said the Black Swan actress. "We have mutual friends. We're comfortable with one another. That's it! There's no crazy love story, nothing more."

But in spite of her recent claims to the contrary, Kunis's previous words may suggest that there is more to the story. In an interview with People in 2001, Kunis revealed that she had a crush on Kutcher during filming of "That 70's Show" and that Kutcher had actually been her first kiss.

"I was like, 'Oh, he's so cute, it's the Calvin Klein model!'" said Kunis, of her first encounter with Kutcher back in 1998. "Then I was like, 'I have to kiss him?' I was so nervous and uncomfortable. I had the biggest crush on him."

 Kunis added that the show's producers gave her perfume to help ease her nerves, which boosted her confidence. "I totally perfumed myself and I was like, 'Hey, I feel better about myself,'" she said. "Ashton was so nice," Kunis remembered. "He just made jokes and gave me funny little compliments. He made me laugh."

Yet the two stars, who continue to be photographed kissing and holding hands in public, still have yet to acknowledge the rumors are true. Both Kunis and Kutcher made recent exits from serious long-term relationships. Kutcher split from his wife of 6 years, Demi Moore, in November. Meanwhile Kunis and "Home Alone" star Macaulay Culkin broke off their relationship in 2010, after dating for eight years.