Jennifer Aniston revealed on Instagram that the Friends reunion will be broadcast on May 27.
It will be shown by streaming platform HBO Max, which also posted the announcement.
The actress, who played Rachel in the hit show, shared the details alongside the message: “Could we BE any more excited?!”
She included a short video of the six cast members with their arms around each other walking away from the camera at what appeared to be the Warner Bros studio lot. It was captioned, “The one where they get back together”.
The famous I'll Be There For You theme song plays gently in the background.
It was also posted on the Friends Instagram account.
One of the first to respond to Aniston was Kaley Cuoco, star of The Big Bang Theory, who wrote: "I can think about nothing else." She followed it up with "Can't breathe".
The show that focused on the lives of six twenty-somethings living in New York City, ended in 2004 after 10 years and 236 episodes. It is one of the most popular TV shows in reruns.
The one-off special will star the original Friends cast, made up of Aniston, Courteney Cox, Lisa Kudrow, David Schwimmer, Matthew Perry and Matt LeBlanc.
It will feature guests including former England footballer David Beckham, pop stars Justin Bieber and Lady Gaga, K-pop sensation BTS and fashion icons Cindy Crawford and Cara Delevingne.
Tom Selleck – who appeared in 10 episodes as a love interest of Monica (Cox) – will take part, as will Reese Witherspoon, who played the sister of Rachel (Aniston).
Filming wrapped in April after several Covid-related delays.
It was billed as an "unscripted celebration" of the US smash hit television sitcom, and will debut on May 27, the streaming platform said.
Parent company WarnerMedia had hoped the reunion would be ready in time to launch its Netflix-rival HBO Max platform last May, before the coronavirus pandemic scuppered production.
It will now arrive on screen exactly one year after the streamer's launch, with its stars reportedly earning $2.5 million each for taking part.
The reunion was filmed at Stage 24 on the Warner Bros Studio lot near Los Angeles, which was the original soundstage for the sitcom about a group of close-knit New York friends navigating adulthood.
A remote or online reunion was never considered because of the significance of the original soundstage, producers said.
Friends executive producers Kevin Bright, Marta Kauffman and David Crane also returned for the special.