From left, Lisa Kudrow, David Schwimmer, Courteney Cox, Matt LeBlanc, and Jennifer Aniston at NBC's "Must See TV: An All-Star Tribute to James Burrows." Chris Haston/NBC It was a no-brainer to the stars of "Friends" that they should be close off-screen, as well. But how?

They explained how they built their bond with some encouragement and space from legendary TV sitcom director James Burrows, whom NBC is honoring with "Must See TV: An All-Star Tribute to James Burrows" on Sunday.

Five of the six "Friends" stars appeared for the special: Lisa Kudrow, David Schwimmer, Courteney Cox, Matt LeBlanc, and Jennifer Aniston.

Matthew Perry was unable to attend, because he's busy with his play, "The End of Longing," in London.

"Whoaaaaaa, we're not all together," LeBlanc corrected host Andy Cohen when he marveled at having everyone there. "There's one missing. We wish he was here. Matty, we miss you."

Although Burrows directed 15 episodes of "Friends," including the pilot, his biggest contribution to the show may be in getting the actors to work on actual relationships with each other — which, in a sitcom environment, can be critical to creating on-screen dynamics.

David Schwimmer, Matt LeBlanc, James Burrows, Jennifer Aniston, Courteney Cox, Lisa Kudrow during the taping of NBC's special. Chris Haston/NBC "[Burrows] really encouraged us all to get along and get to know one another and be kind to one another, and support one another, help one another," LeBlanc recalled.

One way he helped the cast foster their relationships was giving them a space to play poker.

"He gave us his dressing room, because it was big," Kudrow said. "We really wanted to connect. I think it was sort of unspoken, but we instinctively felt like we need to be friends, we need to get along, we need to connect. And so we started playing poker and Jimmy gave us his room, so that we can have a bigger hangout room for us."

Those games, as Aniston pointed out, inspired the "Friends" episode "The One With all the Poker."

Watch the segment of the reunion below: