I found this article on a celebrity blog. I have no idea if this is true, so judge yourself! (source Allie Is Wired)

I have made no secret of my disdain for the show “Heroes.” Quite simply, I see it as a poor man’s ‘Lost.’ However, the show’s incredibly low ratings this season haven’t stopped the show’s cheerleader, Hayden Panettiere from trying to create behind-the-scenes drama.

You see kittens, Panettiere was flashing her 18 year-old business to any 30 something year old that would take notice. And notice was taken by her co-star, the much older Milo Ventimiglia. The two dated and broke up in February of this year.

But Panettiere has her panties in a bunch and is reportedly still holding a grudge against Ventimiglia. According to sources, she is making their on-set interaction unbearable.

“She’s been bad-mouthing Milo behind the scenes to the producers. She gripes about doing scenes with him and flashes him dirty looks when they are not shooting
”

When Milo tried to smooth things over with Hayden, “she acted like she didn’t know what he was talking about,” the source said.

“Hayden told Milo: ‘Will you please get over yourself! Your ego is getting in the way of my acting!’”

Perhaps this is what Milo should have expected when he began dating a girl who listed Big Bird as her inspiration.