G-Girl, Season 5 - Episode 19: It Girl, Interrupted

Serena (Blake Lively) decides she is ready to relinquish the spotlight and sets out to make a reluctant Lola (guest star Ella Rae Peck) the next “It Girl” of the Upper East Side, starting with modeling at a Kiki de Montparnasse lingerie show. Meanwhile, Chuck (Ed Westwick) reaches out to Blair [Leighton Meester] for advice about his past, and Diana Payne’s (Hurley) return to The Spectator starts a power struggle with Nate (Chace Crawford). Penn Badgley, Kelly Rutherford and Matthew Settle also star.

(Source: TV Fanatic)