Ron Palillo Dead: 'Welcome Back, Kotter' Star Dies From Heart Attack At 63

Ron Palillo of "Welcome Back, Kotter" fame has died at 63.

According to TMZ, Palillo passed away after suffering a heart attack at his Palm Beach home Tuesday morning. Palillo was found by his partner of 41 years, retired actor Joseph Gramm, before being transported to a local hospital, where he was pronounced dead.

Palillo was "upbeat, fun, a great friend who loved theater, loved the fans and had a great sense of humor," the actor's agent, Scott Stander, told CNN.

Sources tell TMZ that the '70s TV star, who played Arnold Horshack on the popular sitcom, which starred John Travolta and Gabe Kaplan, was in good health and his death was unexpected.

"Ron was a great colleague and friend," Kaplan told The Huffington Post. "I had been talking about Horshack in my nightclub act and on TV for years before 'WBK' started. When Ron walked into the audition and did his first line 'Hello, how are you? I’m Arnold Horshack' I said, 'That’s him. That’s the guy I’ve been talking about for 5 years.'"

Click over to TMZ for more details.