Tom Bosley Dead at 83

10/19/2010 4:00 PM PDT

Tom Bosley -- Dead at 83

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.