'Friends' Star Matthew Perry Dead at 54 After Apparent Drowning

6:02 PM PT -- More details are surfacing about the circumstances surrounding Matthew Perry's death ... as sources tell us he actually died at his own house after some physical activity this morning.

We're told Matthew came home sometime in the AM after a 2-hour round of pickleball, and that he sent his assistant out on an errand shortly thereafter. We're told when the assistant returned about 2 hours later, he discovered Matthew unresponsive ... and called 911.

Unclear if what Matthew was doing before his passing played any role in his death at this point -- the investigation into his death is underway.

Matthew Perry -- one of the stars of "Friends" -- has died ... TMZ has learned.

Law enforcement sources tell us the actor was found Saturday at an L.A.-area home ... where we're told he appears to have drowned. Our sources say first responders rushed over on a call for cardiac arrest. It's unclear where exactly on the grounds this happened.

Our sources say he was found in a jacuzzi at the home ... and we're told there were no drugs found at the scene. We're also told there is no foul play involved.

Perry is most famous for his role as Chandler Bing on the hit '90s sitcom, which ran for 10 seasons ... and with him in all 234 episodes. His character was a fan fave, as was his performance -- mannerisms and lines of which have gone on to be recreated and spoofed by fans all over the world. One comes to mind, in particular ... "Could (blank) BE more ..."

While "Friends" was his biggest claim to fame ... MP starred/guest starred in countless other TV shows over the years -- such as "Boys Will Be Boys," "Growing Pains," "Silver Spoons," "Charles in Charge," "Sydney," "Beverly Hills, 90210," "Home Free," "Ally McBeal," "The West Wing," "Scrubs," "Studio 60 on the Sunset Strip," "Go On," "The Odd Couple" and more.

He had also acted in a handful of memorable films (mostly comedy) ... like "Fools Rush In," "The Whole Nine Yards," "Three to Tango," "The Kid," "17 Again," "Getting In," and many others. He's been off the scene more recently ... not having acted since a TV miniseries in 2017.

While his onscreen persona was affable and upbeat, Matthew suffered mightily behind the scenes -- notably, from his addiction to drugs and alcohol ... pain killers, specifically. He was hooked on Vicodin for years -- even while on 'Friends' -- and had been in and out of rehab.

Matthew opened up about this painful chapter of his life in a memoir he put out last year -- where he detailed the struggles he had ... including his clear weight loss/gain on the show.

During his press run for his book ... Matthew did a number of interviews where he got incredibly emotional -- including one with Diane Sawyer, where he detailed his story.

While Perry appeared to be clean and sober a year ago, the year prior -- when he and the other cast members were plugging the "Friends" reunion show -- drew concern from fans ... as they felt he appeared unwell, at times slurring his words and looking a bit out of it.

On top of his substance use ... Matthew also dealt with health issues, some of which were serious and required hospitalization. One such incident stemmed from a gastrointestinal perforation -- which forced him to undergo emergency surgery ... but he luckily recovered.

Matthew never married, but he was briefly engaged to Molly Hurwitz a couple years ago ... which came to an end after only 6 months. Before that, he'd been linked to Lizzy Caplan.

He was 54 years old.

RIP