update
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 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.