You’ll never believe what unwritten rule the Friends cast had on set

You'll never believe what unwritten rule the Friends cast had on set as the stars of the show look back on their 10 seasons - and you'll be so shocked you'll spill your coffee.

The cast of Friends had an unwritten rule that they all had to stick to off-camera but you won't believe it.

As Friends fans across the world wait for the highly anticipated Friends: The Reunion show to air, we're busy signing up to watch the Friends reunion show with a free trial on Now TV.

But Matthew Perry, who played Chandler Bing in the hit TV series, has given fans a teaser of what's to come when the cast meets up on set for the first time in 20 years. There were rumours Jennifer Aniston had some baby news for her fellow co-stars but this was later said to be 'false' and 'never happened' according to her reps.

And more juicy details have started to be spilled, as Matthew claimed there was a 'no hook-up' policy in place for the Friends cast throughout their 10 seasons on the air.

With Friends fans asking 'Are Jennifer Aniston and David Schwimmer dating?' as the pair confessed to 'crushing' on each other off-camera.

In an interview with Access, to promote the Friends Reunion show, when asked if there was a pact about not hooking up with co-stars, Matthew, confessed, "There was a rule that we had – it was really important to the six of us that we kept a friendship, that we were friends.

“If we were hooking up, or there was any strangeness going on, that could have messed with things,” he said, claiming that Friends director Jim Burrows was the one to introduce the rule.

He continued: “So we kept a friendship, and we did become really good friends. And we are really good friends to this day. And we kept that going, and I think that was very important.”

Matthew was joined by co-star David Schwimmer, who played Ross Geller, and Matt LeBlanc, who played Joey Tribbiani. David agreed about the rule and added, “It was kind of an unspoken [rule]”, while Matt described their relationships as “more like siblings”.

But when the girls sat down for their interviews, they - Jennifer Aniston, Lisa Kudrow, and Courteney Cox, who played Rachel Green, Phoebe Buffay, and Monica Geller respectively, couldn't remember such a pact. “I think it's a smart idea but I don't remember actually talking about it,” Courteney admitted.

And the girls joked how their male co-stars had made up the rule to hide the fact that none of them were ever interested in them.

But one thing that does live up to the show's theme tune is their united friendship. "Always,” said Courteney, while Jennifer and Lisa agreed, saying, “True”, simultaneously. “And forever and ever until the day we die,” added Jen.