Friends reunion's string of special guests to include Justin Bieber and David Beckham

The reunion we've all been waiting for is edging ever closer and new details have emerged on just who will be appearing on the special.

Shortly after fans of Friends were sent into a frenzy thanks to a brand new teaser for the upcoming reunion special, a list of special guests was unveiled.

In the trailer,Rachel Green (Jennifer Aniston), Monica Geller (Courteney Cox), Phoebe Buffay (Lisa Kudrow), Joey Tribbiani (Matt Le Blanc), Chandler Bing (Matthew Perry), and Ross Geller (David Schwimmer), can be seen walking side by side from behind in a dimly lit street, with a piano version of the theme tune playing.

"Text then reads: "The one where they get back together".

And now fans have discovered just who will make a special appearance alongside everybody's favourite group of friends when the show premieres on May 27 on HBO Max.

HBO Max has announced special guest appearances for Friends: The Reunion (HBOMax/Twitter)

The Friends cast walked together in the trailer for the reunion (jenniferaniston/Instagram, HBO max)

Joining the famous cast will be stars such as BTS, Justin Bieber, David Beckham and Lady Gaga, while many memorable Friends supporting actors will return.

James Corden, Cara Delevingne and Kit Harington will also play a part in what has been described as "a real-life unscripted celebration of the beloved show".

Fans will be excited to see Larry Hankin's Mr. Heckles, a.k.a. The Weird Man who lived in the apartment below the iconic Friends apartment also back on our screens.

And who can forget Joey's Vegas hand double? Thomas Lennon, who played Vegas card dealer Randall, is also set for a cameo appearance.

James Michael Tyler, who plays Gunther, is set to make an appearance on the reunion show (NBCUniversal via Getty Images)

But what would a Friends reunion be without everyone's beloved Gunther?

The Central Perk coffee shop manager, played by James Michael Tyler, appeared in more episodes than any other supporting character or guest star and will once again be involved.

Of course, the show had a string of unforgettable characters and Janice Litman-Goralnik (played by Maggie Wheeler), Dr. Richard Burke (Tom Selleck) and Jill Greene (Reese Witherspoon) are all set for their return too.

Tom Selleck will return to the set for the Friends reunion show (Getty Images)

The iconic series originally ran from 1994 to 2004.

And the eagerly awaited special reunion was reportedly finally filmed in April over three days, with a live audience participating in the reunion.

Little is known about what fans can expect, but portions were said to have been filmed inside the original Friends stage.