HILARY DUFF GUEST STARS — Vanessa (Jessica Szohr), hoping to finally win her mother Gabriela's (guest star Gina Torres) approval, desperately vies with Blair (Leighton Meester) for the honor of delivering the freshman toast at NYU, but at what price? Dan (Penn Badgley) invites Olivia (guest star Hilary Duff) to meet Rufus (Matthew Settle) and Lily (Kelly Rutherford), which leads to all sorts of problems for the new couple. Serena (Blake Lively) and Nate (Chace Crawford) team up to help Carter Baizen (guest star Sebastian Stan).