Lee Thompson Young Ex-Disney Superstar DEAD, Possible Suicide

                       Lee Thompson Young -- who played the main character on Disney's "The Famous Jett Jackson" -- has died after what officials believe
is a suicide ... TMZ has learned.  He was 29.

Sources tell us Young's body was discovered with a gunshot wound that appears to be self-inflicted.

Young currently appears in the TNT show "Rizzoli & Isles" -- and we're told when he didn't show up to work this morning, staffers called the landlord of Young's L.A. home to check up on the actor.

We're told ... when the landlord opened the door, he discovered Young's body.