You will be miss Tom, Mr. C.
Tom Bosley -- who famously played Mr. Cunningham on "Happy Days" -- died this morning at a hospital in Rancho Mirage, CA ... TMZ has learned.
A rep for the Bosleys tells TMZ Tom "died of natural causes or specifically, from a brief battle with lung cancer."
The rep adds, "In lieu of flowers, the family asks that donations be made to the American Cancer Society."
He was 83 years old.