Milo Ventimiglia and Hayden Panettiere

Heroes' stars Hayden Panettiere and Milo Ventimiglia have broken up, and the jury is out as to whether it was 12-year age difference or the new man in Panettiere's life — Jesse McCartney.

The couple called it quits within the last week, according to Usmagazine.com. The magazine said a source close to the couple explained differing lifestyles were at fault for the split: "They were in very different places."

The insider also mentioned that the 19-year-old is young and living the Hollywood lifestyle, which is "not [Milo's] style" now that the 31-year-old is "concentrating on work on his production company [Divide Pictures]." 

But the "different places" explanation may not be the whole truth, now that rumors have surfaced of Panettiere's new relationship with McCartney. The two were seen at the Crown Bar in Los Angeles early last week getting very touchy-feely, according to RadarOnline.com.

The site said the Heroes actress was spotted sitting on 21-year-old McCartney's lap while he kissed her neck. The PDAs were even taken to a new level when Panettiere got up and gave McCartney a lap dance. Wow, not so secretive about this is she?

Why do you think the Heroes lovers split? Do you think we'll see the tension on-screen?