"They were very affectionate and playful," an onlooker at Comic-Don tells PEOPLE
The actor, 39, popped into the Camp Playboy event at Comic-Con last week with Joe Francis’s ex-wife Christina McLarty.
Although approached by wrestler Alicia Fox – who invited him to a party – a chatty Arquette eventually made his way back to McLarty, and the duo “danced the night away together” on Friday, according to an onlooker.
The fun didn’t stop for the pair. On Saturday night, the duo hit up the Entertainment Weekly Comic-Con party.
A rep for Arquette says McLarty was among a group of people with the actor at Comic-Con and that they are not dating.
• Reporting by JENNIFER GARCIA, DAVID SCHLOW and JESSICA WEDEMEYER