When your co-worker becomes your ex, on the next Oprah….

Barely legal sex symbol Hayden Panettiere wants her former boyfriend fired from the cast of NBC’s Heroes, OK! claims.

The 19-year-old blonde beauty has devoted her life to trying to get Milo Ventimiglia, 31, kicked off of the show after her bitter breakup with the actor, according to a snitch.

“She refuses to be on the set at the same time as him,” a mutual friend of the stars spilled to the tab this week. “She is making it difficult for everyone involved.”

As for Milo, “He’s not going to play any games or stoop to her level,” the insider adds.

Perfect example of why it’s a bad idea to date people you work with….Not to mention the problems that arise when men in thirties date teenage girls….