40 People Who Guest Starred on 'Gossip Girl': From Ivanka Trump to Lady Gaga and More

Aaron Tveit joined the cast of Gossip Girl as Trip van der Bilt, Nate's cousin and rival. He appeared in a total of nine episodes in Seasons 2, 3, 5 and 6.

Alexa Chung graced Gossip Girl Season 6 with her presence, as she played a model who refused to appear on stage during a fashion show.

Gossip Girl Season 2 introduced Call Me By Your Name actor Armie Hammer as Gabriel Edwards, the conman who married Blake Lively's Serena van der Woodsen before cheating on her and stealing her money.

Ashley Hinshaw played herself in one episode of Gossip Girl.

The series episode "Valley Girls" offered a backstory of Serena's mother, Lily (Brittany Snow).

Harry Potter star Clémence Poésy guest starred in Season 4 as Eva Coupeau, Chuck's girlfriend.

During Blair Waldorf's 18th birthday, Cyndi Lauper popped out at the party as the "ultimate gift."

Gossip Girl Season 4's last episode saw David O. Russell playing himself, offering Serena to become part of his movie adaptation of F. Scott Fitzgerald's The Beautiful and The Damned.

Florence vocalist Florence Welch serenaded Gossip Girl viewers with a "Cosmic Love" performance in one of the series' episodes.

Gwen Stefani and her band, No Doubt, performed at a club as a fictional group called Snow Out. They sang a cover of "Stand and Deliver" during the scene.

Hilary Duff had a memorable Gossip Girl cameo when she played the fictional celebrity Olivia Burke's role. She had a fling with Dan and got involved in a steamy threesome with him and Vanessa.

Her character left the show for good after announcing she had been cast in a new flick.

Married couple Ivanka Trump and Jared Kushner appeared together at a party on Gossip Girl in 2010.

Karlie Kloss marked her brief appearance on the show as a fashion party guest on the series.

Nate also fell in love with Katie Cassidy's character during the When a Stranger Calls star's brief cameo.

Playing the role of Damien Dalgaard, Kevin Zegers joined the cast of Gossip Girl from 2009 until 2010 as a mischievous Casanova.

Aside from being the voice of Gossip Girl, Kristen Bell appeared in a finale where she read a script based on Dan's book.

A flashback episode featured Krysten Ritter as Lily's big sister, Carol Rhodes.

Gossip Girl Season 3 surprised its viewers when Lady Gaga performed her hit song, "Bad Romance" in front of a massive crowd.

"Stay (I Missed You)" hitmaker Lisa Loeb guest-starred in the Season 1 episode "Woman on the Verge" and Season 6 episode "New York, I Love You XOXO" as a special host of a fictional show and Rufus' girlfriend.

Nate found love again when Riverdale star Mädchen Amick's character appeared on the show. Their relationship lasted for a few episodes during the second season.

Melissa Fumero marked her brief stint on Gossip Girls as one of Blair's minions.

Former New York City Mayor Michael Bloomberg joined the series' episode "New York, I Love You XOXO."

Michelle Trachtenberg joined Gossip Girl and brought the drama as Georgina Sparks.

Olympic gymnast Nastia Liukin appeared in an episode as one of the girls who tried to flirt with Chuck at a party.

Rachel Bilson appeared as herself in one 2012 episode! She joined in reading Dan's script until everyone found out who Gossip Girl was.

Rachel Zoe had an embarrassing part as a guest star on Gossip Girl. She attended Blair's 20th birthday party as herself but made a scene when she fell on the floor and spilled the chocolate fondue over her head.

iZombie star Ryan Hansen was in a flashback episode as a musician friend of Carol's boyfriend.

For 11 episodes, Sebastian Stan swooned in people's hearts as bad boy Carter Baizen.

Tika Sumpter's Raina Thorpe had a quick romance with Chuck during her brief appearance on the show.

Tim Gunn played himself in a Season 4 episode, "Easy J."

The Real Housewives of New York City cast member Tinsley Mortimer attended the Hamptons White Party during her brief cameo.

Supermodel Tyra Banks portrayed the role of Ursula, Olivia's costar, in the third season of the series.

Vera Wang looked ageless when she fitted Blair's gown for her first wedding.