Here's the official synopsis for the 10th episode "The Last Days of Disco Stick"!

Don't forget to check out other spoilers posted about this episode!

GUEST PERFORMANCE BY LADY GAGA! — Hoping to impress the elitist theater kids at NYU, Blair sets her sights on landing a private concert with the hottest musical performer of the year, Lady Gaga. Dan and Olivia sign up to write and star in a school play, based on an idea by Blair and directed by Vanessa. With Blair out of the picture, Serena turns to Nate to help her get through a difficult situation. As a favor to Chuck, Jenny agrees to hang out with Damien, the son of an ambassador who is staying at Chuck’s hotel, but the experience proves to be a lot more intriguing than she expected.

Source: The CW