Milo Ventimiglia and Hayden Panettiere are heating up

Milo Ventimiglia and Hayden Panettiere are heating up.

"Hayden's mom adores Milo. She thinks he's so cute," a family friend tells PEOPLE. "She tells her friends that he's her boyfriend. She's very proud."

On a December trip to New York City, Ventimiglia hung out with the entire Panettiere family. "He's even met her grandparents. He fits in perfectly with the family. Milo jokes around with her little brother," says the source. "They're buddies."

"they're very affectionate and very comfortable around each other. He really takes care of her, even down to the little things like giving her a back massage and going with her to work."

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