Friends Reunion 2016: The reunion of the "Friends" cast happened during a one-time episode to mark director James Burrows' 1,000th television episode.

 "They participated like all the other casts did. They had a question session on the couch with the host where they talked about what it was like working with me," James Burrows told E! News.

Burrows notably directed 15 "Friends" episodes during the first four years of Friends.

"Over the first four years, they had grown into these enormous stars, and had not grown an ego, so that they still were - and still are - great friends," he said. "At the reunion, when they did my special, it was great to see all five of them together," Burrows told E! News.

Kaley Cuoco took to Instagram to post a "Friends reunion" photo. The images was the first in years that David Schwimmer, Matt LeBlanc, Jennifer Aniston, Lisa Kudrow, and Courteney Cox posed together. Johnny Galecki from the cast of another Burrows show: The Big Bang Theory, stood in for Matthew Perry.

The Friends reunion was incomplete. Matthew Perry sent a pre-taped message in his place instead.

Matthew Perry is in London for rehearsals of his playwriting debut, "The End of Longing." The play begins previews on February 2 at the Playhouse Theatre.

"Matthew will not be attending as he is in London in rehearsals for his play, The End of Longing," Perry's rep Lisa Kasteler, said in a statement.

Marta Kauffman, the series' co-creator, has stated there will never be a true Friends reunion movie.

Kaley Cuoco took to Instagram to post a "Friends reunion" photo. The images was the first in years that David Schwimmer, Matt LeBlanc, Jennifer Aniston, Lisa Kudrow, and Courteney Cox posed together. Johnny Galecki from the cast of another Burrows show: The Big Bang Theory, stood in for Matthew Perry.

"It was just lovely to all be in the same room," Schwimmer told ET at the premiere of FX's The People v. O.J. Simpson: American Crime Story.