Welcome Back, Kotter's Ron Palillo Dies at 63

Ron Palillo, best known as Arnold Horshack on Welcome Back, Kotter, has died, according to CNN. He was 63.

Palillo died of a heart attack in his Palm Beach, Fla., home, early Tuesday, his agent Scott Stander confirmed.

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A Connecticut native, Palillo rose to fame playing class clown Arnold Horshack alongside John Travolta on the ABC sitcom that ran from 1975 to 1979. He came up with the character's catchphrase, "Oooh! Oooh, Mr. Kotter." He went on to make appearances on such shows as Laverne & Shirley, CHiPsand Murder, She Wrote. 
The actor was a teacher at G-Star School of the Arts for Motion Pictures and Broadcasting in West Palm Beach, Fla., at the time of his death.
"[Ron was] upbeat, fun, a great friend who loved theater, loved the fans and had a great sense of humor," Stander added.
Palillo's death comes almost seven months after that of his Kotter co-star Robert Hegyes, who also died of a heart attack.
Palillo is survived by his partner of 41 years, Joseph Gramm, a retired actor.