The cheerleader's love life is getting serious. Hayden Panettiere's alleged romantic involvement with Heroes co-star Milo Ventimiglia heats up as she introduced him to her family.

Ventimiglia hung out with her entire family on a December trip to New York City.

"He's even met her grandparents. He fits in perfectly with the family. Milo jokes around with her little brother. They're buddies," a source says.

Panettiere's mom is apparently very proud of the actor. "Hayden's mom adores Milo. She thinks he's so cute. She tells her friends that he's her boyfriend. She's very proud."

The 30-year-old actor reportedly confirmed that he and the actress who plays his niece on the hit TV series are a couple saying he "loves" her.

A rep for the actress declines to confirm the relationship. "We do not respond to inquiries from the media regarding Ms. Panettiere's personal life."