Here it is, the moment you've all been waiting for: Hilary Duff joins the cast of Gossip Girl! She looks kinda like ... Hilary Duff, only on Gossip Girl.

Duff's character, Olivia, is a movie star trying to live the typical college life. Assigned to be Vanessa's (Jessica Szohr) roommate at NYU - their dorm room is the setting of the photo below - Olivia gets to know Dan Humphrey (Penn Badgley).

Olivia becomes attracted to Dan, and vica versa. Of course, there's a twist: Dan is so tuned out to pop culture that he doesn't realize the girl he's falling for is a huge star famous for her role in a Twilight-esque series of vampire movies.

So that's like Dan not knowing who Robert Pattinson and Kristen Stewart are. Come to think of it, that sounds kind of like Dan. It just might work.

Here's Hilary Duff entering her dorm room at NYU ...