Hayden Panettiere Not Dating Mark Sanchez, Says Source
06/01/2011 AT 12:30 PM EDT
So, are they more than just burger buddies?
"They're not dating at all," a source tells PEOPLE. "They're really just friends."
Another source tells PEOPLE that they've been spotted together for months – but maintains they are just friends.
In addition to heavyweight boxer Klitschko, the actress, 21, has also dated her former Heroes costar Milo Ventimiglia as well as Hills alum Stephen Colletti.
Reporting by JULIE JORDAN and BLAINE ZUCKERMAN