Attention Upper East Siders, Kristen Bell and Adam Brody have a special connection.

The duo, who play love interests in the new Netflix romantic comedy Nobody Wants This never worked together prior to their roles as Noah and Joanne, but they are connected by one of Kristen’s former costars, Adam’s wife, Leighton Meester.

And Kristen—who played the ominous voice of Gossip Girl for six seasons—recently broke down the moment she met the actress behind the iconic Blair Waldorf. And it was before they appeared together on the CW series.

“I knew Leighton because she had guest starred on Veronica Mars many, many years before that,” Kristen said during her and Adam’s joint interview with Bustle published Sept. 27. “She was fantastic. And so that’s where I first learned of her and knew her. I had a lot of scenes together with her, that’s where I know her from. But we haven’t really talked about Gossip Girl.”

Kristen, 44, didn’t film in New York City with the rest of the cast which included Leighton, Chace Crawford, Penn Badgely, Blake Lively and Ed Westwick. Instead, she was in a studio in Los Angeles offering her talents.

“I just really loved saying ‘Hey Upper East Siders,” Kristen declared when asked her favorite line from the series during an Oct. 2 interview for Elle alongside Adam. “And figuring out how to make that sound as sassy and as snarky as possible.”

As for The O.C. star his journey with his wife looks a little different. Adam and Leighton—who share 8-year-old daughter Arlo and a 3-year-old son—began dating in 2013 and secretly tied the knot in 2014. The couple—who both rose to fame in shows created by Josh Schwartz—have kept their relationship largely out of the spotlight. 

While Leighton hasn’t spoken out about Kristen and Adam’s onscreen connection, Kristen’s husband, Dax Shepard, has given it his seal of approval.

“Even I can acknowledge watching it, like, ‘Whoa, that’s hot,’” The Bad Moms star said of her chemistry with Adam during a recent eTalk interview. “My husband said the same thing. Like, watching the first episode he was like, ‘Oh my god, I want you to kiss him so badly.’”

Keep reading for juicy Gossip Girl secrets...

Gossip Girl wouldn't be the same without Taylor Momsen. So it's hard to believe that Lily Collins almost played Penn Badgley's little sister. The Emily in Paris actress shared that she went through the entire audition process, lamenting to Glamour, "I wanted it so badly."

Ed Westwick opened up about his onscreen chemistry with Leighton Meester—aka the Blair to his Chuck. On the Feb. 2 episode of the XOXO podcast, he admitted, "I had an amazing time working with Leighton. And people really were taken with that relationship. It means so much to people, which is so cute and funny." 

As for his true dynamic with Leighton, he shared, "She's an incredible talent. I miss her dearly. We just had this great chemistry, and we used to make each other laugh and I felt protective over her at times. Yeah, she probably made me better."

Ed and co-star Chace Crawford (Nate) got extra close, because they actually lived together for the first two years of filming.

As Ed revealed in February, "Chace and I agreed to live together on the pilot. He was like, 'Do you want to room together?' I'd never lived outside my parents' house and I was like, 'Yeah, sure, whatever.'"

The British actor explained, "He went and looked at some places, and he sent me the strangest photos. It was like the corner of a ceiling with a little bit of the floor." Laughing, Ed noted, "I was like, 'Alright, sure. Whatever dude, looks fine!' And so we lived together for the first two years."

None other than Jennifer Lawrence auditioned to play Serena van der Woodsen on Gossip Girl, a part that ultimately went to Blake Lively. While speaking on the Feb. 2 episode of Jessica Szohr's podcast, casting director David Rapaport said that, looking back, it's "wild" that J.Law auditioned.

Gossip Girl casting director David Rapaport dished about the Gossip Girl spinoff centered on Serena's mom, Lily van der Woodsen, with a pilot that starred Brittany Snow and Krysten Ritter. "I remember for that Dakota Johnson came in and Rooney Mara, and a lot of other women who are now kind of big names but at the time didn't have that kind of stature," he recalled of the casting process.

He told host Jessica Szohr, "And you know who did the best read for that? I'll tell you, because I think you're friends with Nina Dobrev, that was one of the best auditions I had ever seen, and for that role specifically."

David said he called the network and told them, "She is a super star." As he recalled on the podcast years later, "She does not look like Kelly Rutherford, because she was supposed to be a young Kelly Rutherford, so I don't know how we would cast her, but she needs to be on your radar and you guys need to find something for her. I just remember thinking, 'I am going to think about this girl in a couple of years and be like, 'Oh god, I missed that opportunity.' She was so incredible!"

As Ed shared on the XOXO podcast on Feb. 2, "Chuck Bass was supposed to be a reoccurring role and was only supposed to come in for a few episodes."

The actor said he feels "lucky" that the mogul became a bigger part of the show, adding of his audition process, "I kind of got around one of the testing aspects there, because I didn't have to test like a series regular. I did two auditions and then a screen test but I never had to test for network." 

Is this considered a meet-cute? Gossip Girl showrunners Josh Schwartz and Stephanie Savage knew that they had found Vanessa Abrams when Adam Brody, who they had worked with on The O.C., brought Jessica Szohr along as a guest to a Fourth of July pool party.

Stephanie said on an episode of XOXO with Jessica Szohr that she and Josh immediately ran to a computer—after all, this happened all before the iPhone came out—and Googled Jessica to see if she was an actress.

Fortunately for the pair, she is!

According to Josh, casting Ed Westwick in the series "was a whole situation." Not only had the English actor initially auditioned for the part of Nate Archibald and lost it to Chace Crawford, but his role of Chuck Bass nearly went to somebody else as well.

"He got cast as Chuck and then couldn't get his visa to come shoot in the U.S. in time, because he was a citizens of the U.K.," Josh recalled on an episode of the XOXO with Jessica Szohr podcast, adding that the network was pressuring him to recast the part.

"They were saying to us as we got closer and closer to start of the pilot, 'Guys, you need to figure out who your back-up Chuck is gonna be because we don't think this is gonna work out,'" Josh remembered. "And we were just like, ‘There is no backup Chuck. It's Ed.'"

Since Josh and his co-creator, Stephanie, were adamant on having Ed play Chuck, the network waited for his visa to get approved.

When Penn Badgley was auditioning for the part of Dan Humphrey, he was rocking what Josh and Stephanie recalled as long, "snowboarder" locks. The actor ended up chopping most of it off on his first day of filming, shocking the crew and network execs.

"Everybody was like, ‘What is happening?! He shaved his head!'" Josh recalled. However, once they all saw the new ‘do, everyone agreed: "Oh damn, he looks good."

Although Kristen Bell was the No. 1 pick for the voice of Gossip Girl, both Christina Ricci and Selma Blair were "in the mix" as possible candidates, according Stephanie, who also served as executive producer. Kristen was cast after Veronica Mars, on which she also did voiceover work as the show's titular narrator, got canceled.

For the creators, the last scene of the pilot—in which Blair (Leighton) and Chuck (Ed) look on as the Humphreys leave a party with Serena (Blake)—was the kick-off point of the iconic couple's relationship.

"There was just a connection between them...that was immediately so palpable and fun," Josh said of the scene. "That was where it kind of really first landed."

"It was like a revelation to watch," Stephanie added. "It's like Dangerous Liaisons. It's like Valmont and Merteuil...they love each other but they hate each other, and they do schemes together. That was such a juicy story to lean into."