Spotted: Blair and Little J, fighting over a microphone, a tube of liquid eyeliner and a pair of spandex pants. Hollywood Life claims relations are strained on the set of "Gossip Girl" because Taylor Momsen, 16, feels co-star Leighton Meester, 23, is enjoying far more support from the CW for her rock 'n' roll aspirations. While both starlets have released singles and belted their little hearts out onstage in New York, only Meester's ditties ("Somebody to Love" and "Good Girls Go Bad") have made the small-screen cut. "Taylor is not happy that 'Gossip Girl' has been playing Leighton's music on the show, and they have never asked to play any of her songs," alleges a snitch. "It's creating a lot of tension on set." Part of the problem: Momsen's band, the Pretty Reckless, may be a little too hardcore for the scheming Upper East Siders. "Leighton's pop music fits the theme of 'Gossip Girl' more than Taylor's punk rock songs," says a spy. The official word from the network: "The show will support Taylor and her music when the time is right, but her music is not ready yet."