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.

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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?