Friends at 20: Twenty fascinating facts you probably didn't know

2. Before Friends was called Friends, it was called Insomnia Cafe.

3.Charlie Sheen was so scared when filming his guest appearance in The One With The Chicken Pox that his brother Emilio Estevez stayed on stage with him to give him support.

4. When Courtney Cox first had on her fat suit and makeup in the first flashback episode, Matthew Perry had no idea who she was.

5. In ‘The One With The Jam’, Matt le Blanc dislocated his shoulder jumping onto the sofa.

6.Central Perk was the last set to be built for the pilot. Originally it was going to be a Seinfeld-style diner.

7. When the cast first started filming, director James Burrows borrowed the Warner Bros. plane and took them on a bonding trip to a Vegas casino. He said this would be their “last shot at anonymity”.

8.The fountain scene in the opening credits went on for so long that the cast was still there at 4 am

9. The frame around the peephole in Monica’s apartment originally had a mirror in it. It was broken by a crew member during the early stages of filming, but producers thought it looked good so they left it.

10. Glee's Jane Lynch auditioned for the role of Phoebe.

11. The orange sofa in Central Perk was found in the basement of the Warner Bros. studio.

12. In a nifty piece of casting Marta Kauffman and David Crane got Candace Gringrich, the lesbian sister of Republican politician Newt Gingrich, to play the minister at Carol and Susan's wedding.

13.The producers had to haggle long and hard with NBC's Standards and Practices Department to keep the scene in The One Where Doctor Ramoray dies where Monica and Rachel fight over the last condom.

14. When Tom Selleck filmed his episodes, the team had to reshoot all his scenes once the audience had gone home because there was so much screaming. Crew said it was like the Beatles had arrived.

15. Monica and Chandler's relationship was originally meant to be a fling, with a few episodes of the pair trying to have sex without anyone knowing. But the reaction from audiences was so positive that it rapidly evolved.

16. In his pilot audition, Matt le Blanc had a big gash on his face because the night before he'd tripped and cut his nose on the toilet seat.

17.It took 15 takes to get Joey and Rachel's big kiss.

18. When David Krane and Marta Kauffman started writing the character of Ross, they already had David Schwimmer in their heads.

19. Upon seeing the pilot, the NBC president had his reservations about Friends. He felt that by Monica sleeping with a guy on he first date, the audience would never respect her character after the pilot. As a compromise, the writers did a straw poll with the audience. They were unanimously fine with Monica.

20. Brad Pitt would pick up Jennifer Aniston from rehearsals most evenings and would sneak in the back door to avoid stealing thunder from the show.

Friends: Nation's Top 20 is on Sunday from 10.30 am on Comedy Central