US actor Matthew Perry, best known for playing wisecracking Chandler Bing in the hit '90s TV sitcom Friends, has died at the age of 54.

The actor was found dead at his home in Los Angeles, law enforcement sources told US media.

Friends, which followed the fortunes of six young friends living in New York City, aired from 1994 until 2004.

Its final episode was watched by 52.5 million in the US, making it the most watched TV episode of the 2000s.

The LA Times and TMZ, which first reported that Perry had died, said the actor was found unresponsive in a hot tub at his house.

A Los Angeles Fire Department spokesperson told the BBC that first responders went to an address in the Pacific Palisades area, regarding a "water emergency" of an unknown type, but did not name Perry.

Warner Bros, which produced the long-running show whose global reruns were loved by new generations of viewers, described Perry as a "true gift to us all".

Born in Massachusetts in 1969, Perry was raised in Ottawa, Canada, where he attended elementary school with Justin Trudeau, who later became Canadian prime minister.

Canada's leader wrote on X: "Matthew Perry's passing is shocking and saddening. I'll never forget the schoolyard games we used to play, and I know people around the world are never going to forget the joy he brought them. Thanks for all the laughs, Matthew. You were loved - and you will be missed."

Perry moved to Los Angeles as a teenager. He starred as Chazz Russell in Boys Will Be Boys and also had roles in shows including Growing Pains.

But he became an international star on Friends, a show which followed the lives of six New Yorkers navigating dating, careers and friendship.

The comedy, co-starring Jennifer Aniston, Courteney Cox, David Schwimmer, Matt LeBlanc and Lisa Kudrow, became one of the most successful shows of all time.

Perry was cast as the awkward Chandler Bing, famous for his sarcastic one-liners and his childish behaviour with room-mate Joey Tribbiani. The role earned him an Emmy nomination in 2002.

But while at the height of his fame, Perry was battling with addiction to painkillers and alcohol, and attended rehabilitation clinics on multiple occasions.

In 2016, he told BBC Radio 2 that he could not remember three years of filming during Friends, because of drink and drugs.

In an interview last year, he spoke about how he did not watch the show.

"I didn't watch the show, and haven't watched the show, because I could go, 'Drinking, opiates, drinking, cocaine,'" he said. "I could tell season by season, by how I looked. That's why I don't wanna watch it, because that's what I see.

"But I think I'm going to start to watch it because it's been an incredible thing to watch it touch the hearts of different generations."

Perry experienced health problems including a burst colon in 2018 due to his drug usage, which required several operations.

Entertainment reporter Sean Mandell described the overwhelming feeling in Los Angeles as "shock" and a "ubiquitous response" in not believing Perry had died.

He told BBC News Perry played an integral part in the success of Friends and was someone who was "at the hub of the wheel".

"His character had the perfect combination of whit, but also true heart and it was grounded," he said.

Perry also appeared in several films, including Fools Rush In, Almost Heroes and the Whole Nine Yards - but never found a screen project which came anywhere near matching the huge success and fame he found in Friends.

His later TV work, however, achieved some acclaim.

His role as associate White House counsel Joe Quincy in Aaron Sorkin's The West Wing earned him two Emmy nominations for outstanding guest actor in a drama series in 2003 and 2004. He played the lead role in Sorkin's later series, Studio 60 On The Sunset Strip, then wrote and produced his own show called Mr Sunshine in which he also played the lead character.

His final significant TV project - other than the Friends reunion - was a TV reboot of The Odd Couple, which lasted on American screens for three seasons. In 2017, Perry tweeted he found out it was being cancelled when he arrived on set and discovered his face on the stage door had been painted over with green paint.

Maggie Wheeler, who played Chandler's troublesome ex-girlfriend Janice in Friends, was the first of Perry's co-stars to publicly pay tribute to the actor.

Wheeler said the joy Perry brought to "so many" in his "too short lifetime will live on".

"I feel so very blessed by every creative moment we shared," she wrote on Instagram.

Morgan Fairchild who played Perry's on-screen mother and erotic novel writer Nora Bing, said: "I'm heartbroken about the untimely death of my 'son', Matthew Perry."

"The loss of such a brilliant young actor is a shock," she added.

Cruel Intentions actress Selma Blair said Perry was her "oldest boy friend", adding: "All of us loved Matthew Perry, and I did especially. Every day. I loved him unconditionally. And he me.

"And I'm broken. Broken hearted. Sweet dreams Matty. Sweet dreams."