I'm sure by now you must have seen the sitcom, unless you've been hiding under a rock for the past 15 years. (Yes Friends began 15 years ago in 1994) 

If you're a fan you'll have followed the lives of the six friends over the entire 10 seasons of the sitcom.  If you're like me, you'll also have watched the countless daily repeats.  So you should know all there is to know, right? But what about some of the more obscure facts.

I've chosen 10 of the most interesting little facts about the show which most viewers won't have known about.  

1. A few months before the first episode aired, the pilot was shown to a test audience, who were less than impressed, scoring it a mere 41 out of 100 and classifying it was "week".

2. Lisa Kudrow played Ursula in the 11th episode of the sitcom "Mad About You" way back in 1992. That was a whole two years before the first episode of Friends.

3. In early episodes of the sitcom, Joey and Chandler lived in apartment 4, while Monica and Rachel lived in apartment 5. This was later seen as a problem since 4 and 5 would typically be ground floor apartments and it was known they lived several stories up. In later episodes their apartment numbers were changed to 19 and 20 respectfully.

4. Before airing, the sitcom went through several title changes before settling on the simple "Friends". Possible titles included Friends Like These, Six of One, Across the Hall, Friends Like Us, and Insomnia Cafe.

5. The very first episode was originally titled just "The Pilot", but because every other episode began with the words "The One..." it was later renamed to "The one where it all began". There was however, one exception to the naming convention, and that was the final episode which was aptly named "The Last One".

6. Gunther actor James Michael Tyler was a mere extra in the first season. He earned his re-occurring role, because he was the only one who could work the cappuccino machine. He wasn't even given a name until season two.

7. The full names of the characters are...

• Ross Eustace Geller
• Chandler Muriel Bing
• Joseph Francis Tribbiani Jr
• Rachel Karen Green
• Monica E. Geller (we never learn what the E stands for)
• Phoebe Buffay (She never knew her middle name)

8. For a joke, in the opening episode of season 6, "The One After Vegas", all the opening credits had the names changed to include Arquette at the end. This was because after finishing season 5, Courteney Cox married David Arquette and became Courteney Cox Arquette.

9. In an act of life mirroring fiction, the coffee house "Central Perk" became a reality in 2006 when Mojtaba Asadian, a businessman from Iran registered the name to use on a new franchise of coffee shops. The first of which was officially opened by James Michael Tyler (Gunther) in Dubai.

10. Over 51 million people watched the first airing of the final episode in the US. That made it the 4th most watched series finale, behind three other sitcoms MASH, Cheers and Seinfeld.

Ready to test your knowledge? Then play our Friends Trivia quizzes now at AbsurdTrivia.com