In their statement, Jennifer Aniston, Courteney Cox, Lisa Kudrow, David Schwimmer and Matt said ... "We were more than just cast mates. We are a family. There is so much to say, but right now we're going to take a moment to grieve and process this unfathomable loss."
They added, "For now, our thoughts and our love are with Matty's family, his friends, and everyone who loved him around the world."
TMZ broke the story ... Matthew was found unresponsive in his hot tub, after he'd played 2 hours of pickleball on Saturday morning. Sources say there were no illicit drugs found at his home, though there were several Rx medications including anti-depressants and anxiety meds.