Gossip Girl's production coordinators have moved swiftly to deny reports that high-profile guest star Hilary Duff has held up production on the hit show this summer with her bratty behavior and a number of diva-like demands.

Rumors swirled that Duff had infuriated the show's cast after refusing to leave her trailer as the others waited to film near Manhattan's Gramercy Park neighborhood, causing a massive delay in Gossip Girl filming that day.

A source said, "No one could believe they would actually hold up taping for her. Nobody in the cast behaves like that." But a rep for the hit CW series, however, tells the New York Post that the Duff rumor is "absolutely not true."

The 21-year-old is currently in New York City filming episodes as a guest star on the hit TV teen drama, in which she plays a movie star who enrolls at New York University with a number of the Upper East Siders we know.

We also know she'll be kissing Dan Humphrey.

Steve Marsi is the Managing Editor of TV Fanatic. Follow him on Google+ or email him here.