James Arness -- famous for his role as Marshall Matt Dillon on "Gunsmoke" -- died Friday at his LA area home of natural causes ... a family spokesperson confirms.
Arness played the legendary lawman during the show's impressive 20 year run -- making him a household name and gaining him three Emmy nominations.
Standing at 6 feet, 7 inches ... Arness was said to be a very imposing character on the legendary western ... but offscreen he was described as very shy.
In addition to his long acting career -- Arness was a World War II Army Combat vet and an avid surfer.
He was 88.