Fox411 Exclusive:

Despite his staggering success as the certified break out star of the “Twilight” film franchise, actor Robert Pattinson is still threatened by his co-stars.

Sources tell Fox411 exclusively that Pattinson is not a fan of sharing the spotlight and that he even refused to host “Saturday Night Live” along with his “New Moon” costars Taylor Lautner and Kellan Lutz.

"Rob is threatened by Kellan and Taylor because he knows he's not the only hottie in the 'Twilight' series," says the source. "When SNL approached him to host he was excited - until he found out he would be hosting with Kellan and Taylor. Rob was used to being the only star associated with ‘Twilight’ and now with Taylor's new buff body and Kellan's rise to fame, that's not the case anymore. He doesn't want to share the stage with them on ‘SNL’ because he doesn't think they are serious actors like him and doesn't believe they are on the same level."