The fourth season of the American teen drama television series Gossip Girl premiered on The CW on September 13, 2010, and concluded on May 16, 2011, consisting of 22 episodes.

[1] Blake Lively, Leighton Meester, Penn Badgley, Chace Crawford, Taylor Momsen, Ed Westwick, Jessica Szohr, Kelly Rutherford, and Matthew Settle all return as series regulars.

[9] Blair Waldorf and Chuck Bass try to end their on/off again relationship, but their plans are thrown for a loop when new international love interests for both come into the picture.

Meanwhile, back in New York, Eleanor helps Lily make arrangements for the Fashion's Night Out gathering at the van der Woodsen penthouse.

Dan deals with raising Georgina's newborn son Milo, while Nate meets a potential new love interest, Juliet Sharp.

Not ready to face what he did last spring and in his high school past, Chuck is hesitant about introducing Eva to Lily, Rufus, and Eric.

Swedish singer Robyn makes a cameo performing an acoustic version of "Hang with Me" at Blair's birthday party celebration.

Blair and Dan team up with an old enemy to find Juliet in Cornwall, Connecticut through a tip from Gossip Girl, and uncovers a bombshell about Serena's sophomore year at Boarding school.

A former associate of Chuck's late father, Russell Thorpe, along with his crafty and headstrong daughter Raina, return to Manhattan with some unfinished business concerning Bass Industries.

Meanwhile, Chuck may have finally met his match with Russell Thorpe and his daughter Raina, when they announce that they are planning to take over Bass Industries.

Nate receives alarming news about his father's business prospects when he learns that the Captain and Russell are working together for some nefarious purpose.

Meanwhile, Russell puts his relationship with Raina at risk by using personal information to blackmail Lily in order to destroy Chuck's family legacy.

Meanwhile, Nate helps Raina find out what happened to her mother, while Chuck's hopes about his legacy are crushed with the reveal of devastating information from the past.

[4] Blake Lively, Leighton Meester, Ed Westwick, and Clémence Poésy began filming this season in Paris on July 5, 2010.

[29] However, Szohr began filming on July 9, 2010, the first day of production in New York City along with Penn Badgley, which indicated she would be back sooner than anticipated.

[31] Taylor Momsen appears in one episode titled "Easy J" which aired October 25, 2010, and will return in full series regular status for the second half of the season.

It had also been confirmed that Tate Donovan, who previously worked with show's developers Josh Schwartz and Stephanie Savage in The O.C., would be directing an episode scheduled to air in November 2010.

[33] The Airborne Toxic Event made a special appearance during the season 4 finale "The Wrong Goodbye" as the band for the Constance Billard Alumni party, playing the song "Changing" from their second album, All at Once.

[37][38] Actor Sam Page was cast as Serena's new love interest, a Columbia business professor and Juliet and Ben's cousin, for a four-episode arc.

Boatman played Russell Thorpe, a powerful business tycoon and a former associate of Chuck's father, Bart, while Sumpter portrayed his daughter, Raina.

[43] Tim Gunn and fashion designers Diane Von Furstenberg and Rachel Zoe all made special cameo appearances during the first half of the season.

Whalley was rumoured to play an adversarial role to Kelly Rutherford's Lily van der Woodsen, but turned out to be that of Princess Sophie, Louis Grimaldi's mother.

[58][59] Recurring cast members Nan Zhang and Nicole Fiscella reprised their roles as Kati Farkas and Isabel Coates for the penultimate episode and the season finale.

Becker remained ambiguous on whether he would be joining the series as a recurring or regular cast member during an interview with Zap2it, stating "the answer is in the finale.

"[61] On May 16, 2011, Entertainment Weekly announced that Gossip Girl author Cecily von Ziegesar would be making a cameo for the season finale.

Season four begins with Serena and Blair enjoying their summer in Paris, until the unexpected appearance of Chuck Bass, who is using a false name and cozying up to a new girl.

[80] "Gossip Girl gets by just fine on scandal, secrets, and convoluted plots, but the times where the show most fully escapes guilty-pleasure territory are when it explores compelling, complex relationships."

"[83] Gerard McGarry, from Unreality Shout, said that the season premiere was "brilliant", while Alexis James-blackhead, from Buzz Focus, said that the episode was "less sizzle than fizzle.

"By the time a television show reaches its fourth season, the characteristics of its main ensemble ought to be deeply entrenched and immediately recognizable to regular viewers.

Adams praised the development of Blair and Serena's relationship, declaring their friendship as "the great, central romance of Gossip Girl.