Matthew and Piper back on?

Matthew Perry and Piper Perabo turned heads earlier this week at a Tribeca film fest party for the Friends alum's new movie Numb. "They were on a couch holding hands and he was rubbing her back," says a source. "She snuck into the movie after everyone was seated, then arrived with him at the party but wouldn't take pictures." Perabo and Perry have been linked in the past, although the Coyote Ugly