According to X17, the former High School Musical hunk and Collins were spotted having dinner at a steakhouse in Los Angeles, with onlookers claiming that the pair left together via the back door, sharing in the same vehicle.
A source told the website: "Zac literally ran to the car and jumped in, leaving Lily behind. But Lily kept her cool and took her time. She wasn't as worried about not being seen by us."
The insider added: "She took her time. She probably didn't want to trip in her heels!"
Lily - whose father is legendary musician Phil Collins- previously dated Lautner after starring alongside him in 2010 flick Abduction, before splitting with the Twilight actor last September.
Launter is now said to be in a relationship with high school sweetheart Sara Hicks, with sources telling Us Weekly that they have "been hanging out a lot in LA, seeing a few shows and going to dinner."