Calling all Upper East Siders: It's time for the ultimate trip down Gossip Girl memory lane. Whether you watched the famous CW show in its heyday or have found yourself taking it all in during a Netflix binge, it's safe to say that we all can agree the show is next-level iconic. Over six seasons, we got to know a few privileged teens who never seemed to catch a break when it came to drama. The show inspired many pop culture trends, kicked off loads of successful acting careers, and may or may not have had you wanting an epic headband collection like Blair Waldorf's. 

A show with such a legacy is bound to have a couple of guest stars appear throughout the show, and boy does Gossip Girl deliver—we're talking everyone from Lady Gaga to Tory Burch to Hilary Duff. Allow this list of 40 celebrity Gossip Girl cameos, ahead, to inspire you to A) freak out, B) rewatch a couple of episodes, or C) all of the above. (Hint: C is the best answer.) 

By Bianca Rodriguez

Hilary Duff played fictional celeb Olivia Burke in season three, who had a brief fling with Dan Humphrey. Who could forget that steamy threesome between her, Dan, and Vanessa? Not us!

Before she starred on Mixed-ish, Tika Sumpter played one of Chuck Bass's many flings. We wanted the couple to work out, but it didn't help that she was Raina Thorpe, a.k.a, the daughter of Russell Thorpe, who tried to buy Bass Industries.

Nate Archibald dated around during the show's six-season run, but no one stood out like Elizabeth Hurley as Diana Payne. The editor-in-chief of the New York Spectator naturally stirred up some drama, even when the characters were living in L.A.!

Sofia Black-D'Elia played Nate's final and youngest girlfriend of the show, Sage Spence. Surprise, it didn't work out...probably because she was a high schooler?

The Harry Potter actress played Chuck's French girlfriend in season four. Unfortunately for Ms. Eva Coupeau, things got rocky when they arrived in New York together.

Who could forget the iconic train wreck that was Georgina Sparks, played by Michelle Trachtenberg, who had a major crush on Dan? She appeared on several drama-filled episodes.

Kevin Zegers played the son of a Belgian ambassador, Damian Daalgard, who got Jenny Humphrey in all sorts of drug-related trouble when they were dating.

Yes, the actual former mayor of New York made an appearance on the show during the final episode when Gossip Girl was revealed! Do we think he still has this shirt?

The Arrow actress played Jenny Humphrey's roommate and business partner, Agnes Andrews. Things turned sour, though, when Agnes sabotaged Jenny's meeting with Tim Gunn (more on that later) by burning all of her dresses ahead of the meeting.

Who could forget the trés sexy Carter Baizen? Fun fact: Sebastian Stan and Leighton Meester dated off screen for two years before splitting in 2010.

Nate's hot older cousin, Tripp van der Bilt (Aaron Tveit), was one of Nate's main rivals. That didn't stop him from hooking up with Serena (when he was married)!

The Real Housewives of New York City star appeared in two episodes of the show as herself—one of those being the Hamptons White Party episode.

Lola Rhodes, played by Ella Rae Peck, was an interesting character. From her romance with Nate to figuring out if she was related to the van der Woodsen family, our heads are still spinning.

Florence Welch and her gorgeous voice made two quick music cameos, in seasons three and four, when she sang "The Dogs Days Are Over" and a cover of "Cosmic Love."

Before he made us cry in Call Me By Your Name, Armie Hammer played Gabriel Edwards, one of many Serena van der Woodsen boyfriends. His downfall? Trying to get her to invest in his "philanthropy" project that was a scam. 

The supermodel played Hollywood starlet Ursula in season three. She got close with Serena after Serena told the actress that her best scene in the movie would be cut, despite the publicist telling Serena to keep it a secret.

I know what you're thinking...WHAT?! But yes, it's true. Before Ivanka's dad occupied the White House, she and husband Jared Kushner made an appearance on the show posing as some of Lily van der Woodsen's friends.

Before she was Betty's mom on Riverdale, Mädchen Amick played Duchess Catherine Beaton, who had an affair with Nate in season two. 

Yeah, so you know how we mentioned that Jenny's fashion career got sabotaged in front of some pretty big fashion people? Tim Gunn was one of them.

In season four of the series, Karlie Kloss played herself as someone looking for Eleanor Waldorf, Blair Waldorf's mom, at a fashion party.

The Grammy-winning artist premiered in a throwback episode as the band who opened for Rufus. Things came full circle when she appeared in the last episode as his new girlfriend.

Fashion's It-girl played herself in season six as a model who refused to go on stage after Blair's fashion show took a wrong turn.

Famous stuntwoman Zoë Bell played Chuck's Los Angeles fling for one episode in season five. Things ended when she basically told him to stop using their date to avoid his problems. Ouch!

This Baldwin brother played Serena and Eric's absent father, William van der Woodsen, who did so many shady things but somehow was still accepted by his family in the end. Ah, television!

During a party at the Waldorf house in season two, the famous singer casually stops by, thus commencing Blair and Dorota to freak out. (Same.)

Ashley Hinshaw played herself in season three and was set out on a mission to play matchmaker for Chuck and Blair. This episode was rather...interesting.

Brooklyn Nine-Nine 's Melissa Fumero was one of Blair's minions when she attended Columbia University, and boy did they get into some trouble!

In season two's throwback episode, the No Doubt singer played a member of a band that performed at one of the clubs young Lily van der Woodsen liked to visit.

I'm still not over the fact that Blair got fitted by Vera freakin' Wang for her first wedding to Prince Louis Grimaldi! While the marriage may have been a flop, the dress was spectacular!

Brittany Snow was a part of the flashback episode from Lily's past life. The Pitch Perfect actress played the lead role of a younger Lily.

Again with the throwback episode mention, but I'm still not over Krysten Ritter as the younger version of Lily's younger sister, Carol.

A personal favorite music cameo was Lady Gaga in season three when she sang "Bad Romance."

Things got messy when the fashion designer attended Blair's 20th birthday party and accidentally spilled an entire bowl of melted chocolate all over herself.

Nastia Liukin, Olympic medalist, showed up in season two and played one of the many girls who flirted with Chuck at the annual Snowflake Ball.

Serena casually scored an internship with the famous designer in season three despite having no experience whatsoever.

Loyal Gossip Girl fans know that Kristen Bell is the one who narrates the entire series as the mysterious Gossip Girl. So, it was the perfect full circle moment when she made an appearance in the final episode.

Another last episode appearance came from The O.C. 's Rachel Bilson when she auditioned for the role of fictional Blair for the soon-to-be movie based on Dan's best-selling book.

How could we forget one of Serena's biggest enemies, Juliet Sharp, and the main reason for many problems in season four? She was also one of Nate's many girlfriends.

In season two's throwback episode, the Veronica Mars actor played someone younger Lily met at a club.

It wouldn't be right if the author of the original book series didn't appear in Gossip Girl. Cecily Von Ziegesar finally makes her debut in the last episode of the show. She tells Serena she "doesn't know" her, but has "read a lot about her." Incredible.