The best celebrity guest appearances in the 'Friends' reunion: Lady Gaga, Cindy Crawford, Justin Bieber and more

By Zach Harper

Over the course of 10 years, Friends featured dozens of celebrity cameos, from Brad Pitt to Julia Roberts to Bruce Willis and Reese Witherspoon. Whether it was Reese playing Rachel's sister Jill to Tom Selleck as Monica's boyfriend Richard, the show became a magnet for A-listers having fun in roles that are still very memorable to many Friends fans 17 years since the show ended.

So of course, it makes sense that HBO Max's Friends: The Reunion special also featured plenty of celebrity cameos. We've rounded up some of the best for you, from Lady Gaga's hilarious duet to Cindy Crawford taking a turn in some pants you'll likely recognize.

The reunion special, hosted by James Corden, began with all six cast members – Jennifer Aniston, Courteney Cox, Lisa Kudrow, Matt LeBlanc, Matthew Perry and David Schwimmer – all meeting at Sound-Stage 24 at Warner Studios for the first time since 2004. The entire set had been recreated, and it was a very emotional moment for them all. The rest of the special featured James interviewing them in front of the fountain from the show's opening credits, interspersed with them all touring the set and their old dressing rooms.

Those who haven't yet watched the reunion special, which dropped May 27, should proceed with caution, as this piece definitely contains spoilers.

Lady Gaga

An incredible moment came when Lisa was running through her hilarious "Smelly Cat" (co-written by The Pretenders' Chrissie Hynde) during the special. Seated on one of the couches on the Central Perk part of the set, she was strumming along and singing Phoebe Buffay's much loved, still hilarious tune when a door opened and in walked Gaga.

Photo: © HBO Max

The superstar – who, wouldn't you know it, just happened to have a guitar – asked if she could take a crack at the song and belted out the chorus in a way only Gaga could. As luck would have it, a gospel choir was also behind them.

Reese Witherspoon

Reese wasn't at the Stage 24 set for the reunion, but made an appearance to speak about how excited she was to play Jill, Rachel's sister, on the show. She also shared her thoughts on how the show managed to resonate with audiences for 10 years.

"If you think about Monica or Phoebe or Rachel, each one of them is a leading character," she said, as her clip was interspersed with footage of the six table reading the episode "The One with the Jellyfish."

"The One with the Jellyfish" was one of several episodes the cast table read during the HBO special. Photo: © HBO Max

"But together, you get this great repartee, all the actors at the top of their game and great chemistry," Reese continued. "They were funny, they were engaging, they knew their characters so well, but they also worked so well together. There was a real sense of love for each other."

David Beckham

The former pro soccer player made the revelation that he thinks he's most like Monica out of all the characters, because he's "a clean freak." He also said his favourite episode is the one where Chandler gets mad at Joey for taking his seat and Joey takes the cushions from the chair with him when returning home from Monica's apartment and says he's "taking the essence" of the chair with him.

"It's one of those episodes that when I'm away and I'm feeling a little bit low, I just put it on and it makes me smile to almost the point of crying," he adorably said.

Justin Bieber

Remember Ross's Spudnik costume? If you don't, it came during the episode called "The One With The Halloween Party." In it, he came dressed in a giant potato costume with a colander and "antennae" on his head. It was meant to be a nerdy joke about Russian satellite Sputnik. Justin showed up wearing it during a fashion show of iconic Friends costumes later in the reunion special.

Photo: © HBO Max

BTS

The beloved South Korean pop stars appeared in a segment in which the show's global impact was discussed, with it being pointed out it had been dubbed into languages from French to Hindi.The same portion also featured ordinary people – and Nobel Peace Prize Malala Yousafzai – discussing how the show had gotten them through difficult times or taught them something important.

RM from BTS said he had learned English by watching Friends because his mother bought him the entire series on DVD. He started watching it with Korean subtitles on, and then eventually didn't need them!

Tom Selleck

As mentioned, Tom played Monica's boyfriend Richard on the show. He joined the cast during a trivia game being MCed by David where they had to first identify his voice on an answering machine message. Courteney got it instantly, but second-guessed herself before Tom came through the door of Monica's apartment and revealed himself.

Tom and Courteney in Season 2 of Friends. Photo: © Paul Drinkwater/NBCU Phobo Bank/NBCUniversal via Getty Images

Christina Pickles and Elliot Gould

The stars, who played Ross and Monica's parents, appeared during a segment where audience members asked the cast a question. They shared their memories of shooting the episode in which the Gellars' parents visit, and said they were always struck by how kind the entire cast was to them.

"One day we came to work, and they said, 'The parents are here! The parents are here!' And it was so moving. We really did feel like their parents. In fact, we used to worry about them quite a lot because they're so sweet."

Cindy Crawford

A bit later in the episode, someone who really could fit in to the pair of leather pants Ross struggled into in "The One With All the Resolutions" showed up for the fashion show. While he tried – and failed – at getting them on, Cindy Crawford certainly didn't!

Photo: © HBO Max

Cara Delevingne

The supermodel was also part of the aforementioned fashion show, wearing Rachel's bridesmaid dress from "The One With Barry and Mindy's Wedding."

Photo: © HBO Max

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