8:21 AM PT -- 12/11 -- Lister had been experiencing COVID symptoms in the days leading up to his death ... according to his manager, Cindy Cowan.
Cowan tells CNN that Tiny began feeling sick a week ago, but he got worse quickly -- couldn't breathe and felt very weak.
She says he was supposed to work on a movie set last weekend but had to cancel due to his breathing difficulties, and he also canceled a Zoom appearance for a TV festival Wednesday. That night is when Cowan says friends and family tried to call and check on him, but their calls went on answered.
7:08 PM PT -- A release from The L.A. County Sheriff's Department says friends and business associates of Lister became worried Thursday when they hadn't heard from him since Wednesday night. Deputies performed a welfare check where they made their way into his apartment and found him dead.
At this point, cops say it's believed that Lister died of natural causes ... but an autopsy will be performed to determine an official cause of death.
Ice Cube, who starred in "Friday" posted a tribute, saying, "RIP Tiny “Deebo” Lister. America’s favorite bully was a born entertainer who would pop into character at the drop of a hat terrifying people on and off camera. Followed by a big smile and laugh. Thank you for being a good dude at heart. I miss you already."
Tommy "Tiny" Lister -- famous for playing intimidating, but lovable tough guys in films like "Friday" -- has died ... TMZ has learned.
Law enforcement sources tell us they got a call to the actor's Marina Del Rey apartment Thursday, just before 3 PM, for an unconscious male. Our sources say Tommy was not transported to the hospital, as he was pronounced dead on the scene.
We're told the coroner is at the home, but there's no word yet on a cause of death.
Though "Tiny" began landing his bullying bad guy roles in the '80s, he's most famous for his hilarious turn as Deebo in "Friday" and the sequel, "Next Friday."
He also played President Lindberg in the sci-fi action film, "The Fifth Element," and more recently appeared in the box office smash hit, "The Dark Knight." He voiced the character Finnick in "Zootopia" as well.
Along with acting, Tommy had 2 short pro wrestling stints, and starred alongside Hulk Hogan -- as the bad guy, Zeus, of course -- in the 1989 film, "No Holds Barred."
Oh, and if ya didn't know, his nickname is pure irony ... "Tiny" was 6'5".
When we last saw him out and about, "Tiny" couldn't have been nicer ... talking to us about another Deebo currently playing in the NFL, and dishing out some new "Friday" info.