Tim Gunn Tim Gunn

Just when you thought Gossip Girl couldn't get any more fashionable, the CW series has decided to up the ante with the addition of Project Runway mentor Tim Gunn.

Fall preview: Get scoop on new and returning shows

Gunn will guest-star as himself in an upcoming episode airing late October. Season 4 kicks off Monday, Sept. 13 at 9/8c.

The casting news was first reported by Entertainment Weekly.

Do you think Gunn will make it work?

Check out the new trailer: