Katie Cassidy Will Leave 'Monte Carlo' Behind For 'Gossip Girl' This Fall

Katie Cassidy and Chace CrawfordBy Eileen Reslen

Spotted: Nate Archibald seen sharing a kiss on campus with a sexy blonde- but wait, that’s not Serena! Uh oh, looks like there’s a new girl in town … but what secret is she hiding?

Expect Gossip Girl to send messages somewhere along those lines come this fall, because according to EW, Katie Cassidy will be joining the cast for multiple episodes in Season 4 as a Columbia student and none other than Chace Crawford’s steamy romantic interest.

Katie's return to the network for "Gossip Girl" reprises quite a similar role to one that she played on that other (dare we say “short-lived”) CW show, "Melrose Place."

“Cassidy’s character will make trouble for several Upper Eastsiders,” a source told EW's Michael Aussiello. “She is not what she appears.”

Watch out Blair, looks like someone may be gunning for your title as Queen B!

Well, we predict the relationship between this catty pair can go one of two ways: either they face off to see who can come up with the most vindictive schemes or they will plot together for a super mega-force of snobby bitchiness.

Leighton Meester may have her hands full because Katie’s dealt with bigger monsters before (like a nightmare haunting killer!)

Whatever the dynamic may be on-screen, off-screen you may be surprised to learn that these two get along just like BFFs! Leighton and Katie are both currently filming teen adventure “Monte Carlo,” in which they (along with Selena Gomez) head to Europe for a backpacking trip.

But does what happen in Europe, stay in Europe? We’ll find out when the new season premieres and these frenemies will have fans picking sides. Still, we should mention that Katie’s captured our hearts before in our weekly Girl Crush column, so let’s see if she can charm us again.

You know you love her, XoXo.

Are you happy Katie will be seen on "Gossip Girl"? Do you think seeing her place a bitch or do you want to see her branch out more?