Friends Reunion: The One with Lady Gaga, BTS, Justin Bieber and David Beckham

All the celebrity cameo appearances in the long-awaited show, from Cara Delevingne to Cindy Crawford

Lady Gaga joins Phoebe (Lisa Kudrow) for a rendition of 'Smelly Cat', a song made famous in the original 'Friends' sitcom. Courtesy HBO Max

For the first time in 17 years, Jennifer Aniston, Courteney Cox, Lisa Kudrow, Matt LeBlanc, Matthew Perry and David Schwimmer gathered in the same room for the highly anticipated Friends: The Reunion.

A look back at the sitcom that ran from 1994 to 2004, the unscripted reunion show saw host James Cordon guide the famous six through a nostalgia-laced journey of memories, bloopers, outtakes and more.

But the HBO Max special didn't only reunite Joey, Phoebe, Chandler, Monica, Rachel and Ross; the original cast were joined by a host of famous faces.

Ross (David Schwimmer) recreats a quiz game in the same format as the one that saw Rachel and Monica lose their apartment in season 4 of 'Friends'. Courtesy HBO Max

Elliott Gould and Christina Pickles, who played Ross and Monica's parents on the show, were seated in the socially distanced audience, and Central Perk's coffee shop manager Gunther, played by James Michael Tyler, joined via a live video link.

Actor Tom Selleck – Monica's boyfriend Richard in the second season of the sitcom - joined the cast on a recreation of the original Friends set to ask a question in Ross's (Shwimmer's) quiz show. A barbershop quartet that Ross originally hired in the show stopped by to remind Rachel, again, that it's nice to have a boyfriend. Larry Hankin, the now 80-year-old actor who played Monica's neighbour Mr. Heckles, also popped in, grumpy as ever.

Maggie Wheeler – Chandler's loud-talking ex-girlfiend Janice – joined the cast and Cordon in the studio and Joey successfully picked out his hand-twin, aka Thomas Lennon, from season five. And it wasn't only former cast members who got involved.

A host of new celebrity faces joined in, either in-person at the Warner Bros Studio lot in Burbank or via pre-recorded video messages. Here's who made an appearance...

Lady Gaga

Joining Lisa Kudrow on the couch for a rendition of Phoebe's Smelly Cat ballad, Lady Gaga added her throaty vocals and guitar strumming skills to Kudrow's most famous song. A six-piece choir also joined the ladies for a new rendition of the song made famous in the sitcom. The popstress went on to thank Lisa for being the "different one, or the one that was really herself", to which Kudrow responded, "thank you and thanks for carrying it along".

Justin Bieber

Justin Bieber as 'Spudnik' on the 'Friends' reunion special episode. Courtesy HBO Max

Despacito singer Justin Bieber appeared as a model in the HBO studio, taking to the runway in the 'Spudnik' costume from Season 8 of Friends.

Originally worn by Ross, Schwimmer told the audience that he'd been embarrassed to wear the costume as it was in the same episode that starred Sean Penn.

“We get the script and, of course, I realise, ‘Oh, I’m a potato’,” said Schwimmer. "I had very little – if any – dialogue with him, but here I’m thinking, ‘Greatest actor in the world, and I’m a potato’.” Bieber didn't seem to share the same embarrasment and was in good spirits, strutting along the catwalk and pulling faces to the camera.

Cara Delevingne 

Supermodel turned actor Cara Delevingne also starred in the reunion fashion show, modelling not one but two costumes from the sitcom. First, she strutted out in the pink bridesmaid dress worn by Jennifer Anniston in Season 2 at the wedding of Rachel's ex-fiance Barry. The British star then rejoined the catwalk in perhaps the most famous Friends costume of all, Schwimmer's Holiday Armadillo.

Delevingne said on social media that she grew up watching the show and felt lucky to be included. "Could I BE any more excited? Being a part of the Friends reunion was truly a dream come true … Plus, I got to be the HOLIDAY ARMADILLO,” wrote the model.

Cindy Crawford

Cindy Crawford in Ross's leather trousers. Courtesy HBO Max

There was no shortage of supermodels in attendance for the sitcom reunion, with 51-year-old Cindy Crawford also taking to the runway. Once America's most celebrated fashion model, Crawford recreated one of Ross Geller's most embarrasing fashion moments in Friends by wearing the tight black leather pants Schwimmer wore in Season 5. Crawford paired the pants with a silk button-down shirt similar to the one Ross wore in the original episode, but pulled off the look a whole lot more easily than the hapless palaeontologist.

BTS

Fresh from clocking up five new Guinness World Record's for their latest smash hit Butter, K-Pop kings BTS also appeared on the Friends Reunion. All seven members of the world's biggest boy band crowded on a sofa and RM, who was born in the same year that Friends launced, revealed that the show played a big role in teaching him English.

Reese Witherspoon

Reese Witherspoon appeared in the 'Friends' reunion talking about her time on the show as Rachel's sister. Greg Allen / Invision / AP

This is a bit of a cheat listing, as Reese Witherspoon actually starred in The One with Rachel's sister, playing Jill Green. But the Hollywood star also made a video appearance on the Friends Reunion.

The Legally Blonde star told viewers that she felt like she had won the lottery when she got invited on the show. Witherspoon also gushed over Joey's (LeBlanc) reaction to her appearance in the show.

"The most exciting part was that I got to be in a scene where I'm in the apartment and Joey walks in and he goes 'Hey, how you doin'?'."  The line was Joey Joey Tribbiani's catchphrase, which he used whenever he wanted to start chatting to women.

Mindy Kaling

Comedy actor Mindy Kaling appeared via a pre-recorded video to share her love of the original Friends sitcom. The Mindy Project star spoke of her memories of watching the show, revealing that The One With All The Kissing was one of her favourite episodes. Aired in 1998 during Season 5, the episode was one of the first to document Monica and Chandler's blossoming relationship after their trip to London. On Twitter, Kaling sarcastically commented about her idea to film the message for the show while heavily pregnant and using her mobile phone.

Kit Harrington

Game of Thrones star Kit Harrington appeared on the show with a video message in which he claimed to be part of the Geller family. The Jon Snow actor in the fantasy drama series said in a pre-recorded video that he felt he could easily be part of the Geller clan because he is as neurotic as Monica (Cox), and wears tight trousers like Ross (Schwimmer).

David Beckham

Former professional footballer David Beckham appeared on the Friends reunion telling viewers that he often watched the sitcom when he was working away from his family. Getty Images

David Beckham, one of the world's most famous footballers, had a cameo video appearance on Friends: The Reunion. The former Manchester United, Real Madrid and AC Milan star said that he travels a lot and watches Friends when he had downtime away from the family.

Beckham, who is married to former Spice Girl Victoria, said his favourite episode was The One Where No One's Ready. Marta Kauffman, co-creator of the sitcom, then revealed that this episode was filmed in real-time and ended up with LeBlanc dislocating his shoulder as Joey and Chandler fought over a chair in Monica and Rachel's living room. It's also the episode where Joey puts on all of Chandler's clothes at once, a moment that the 53-year-old actor recreated as part of Friends: The Reunion.