Mila Kunis and Ashton Kutcher won’t define their relationship — but they’re not being shy about the affection they have for one another. Details after the jump.

Although the former That 70s Show costars won’t confirm rumors of a romance, they were spotted showing major PDA during a weekend lunch in Los Angeles.

A witness told Us Weekly:

“They were seated on a couch on the same side of the table and Mila was running her hands through Ashton’s hair. She had her elbow resting on his back and couldn’t stop playing with his hair and rubbing his shoulders. He leaned in and whispered to her and kissed her cheek. They were holding hands.”

Insiders say that the two are in fact dating — but their relationship is not exclusive.