Ron Palillo, who played Arnold Horshack on the 1970s comedy show "Welcome Back, Kotter," has died at age 63.

The actor passed away early on Tuesday, August 14, his rep told OnTheRedCarpet.com. He had suffered a heart attack near Palm Beach Gardens, Florida, his agent told CNN. The Palm Beach Post newspaper quoted a friend of Palillo's as saying that he died earning that morning.