Hayden Panettiere "Didn't Want People Thinking She's a Ho"

The romance between Heroes stars Hayden Panettiere and Milo Ventimiglia has been an open secret for months �" in part because of their 12-year age gap."They were tired of avoiding questions and of all of the effort of keeping it secretive," a Panettiere source tells Us Weekly.

Panettiere, 18, who plays Ventimiglia's niece on the hit show, was also worried about her reputation. "She didn't want people thinking she is a 'ho' because she jumped from one relationship into another."

Indeed, Ventimiglia, 30, had a crush on his co-star since she was dating Stephen Colletti. "He always had a crush, but really let her know the minute she broke up with Stephen," a source says.

Since Panettiere still leaves with her mom, it's a good thing, a source tells Us, that Ventimiglia has her approval. "Milo is such a good guy, honest and sweet," says a source. Besides, says another source, "She is really like a 30-year-old."