'Gossip Girl' 4.19 Sneak Peek: Blair's Secret Date

Blair is welcoming a special guest in next episode of "Gossip Girl" as Prince Grimaldi is in town. Planning to miss a class to have a date with Hugo Becker's character, the Waldorf girl cannot tell her friends with whom she will be spending the night. Also in "Petty in Pink", Blair and Dan's secret affair is in danger to be uncovered with Serena sending Charlie (guest star Kaylee DeFer) to go