TMZ is reporting that actor Ron Palillo who played Horshack on the 70's TV show "Welcome Back, Kotter" has died at the age of 63.

Reports say he died of an apparent heart attack at his home in Palm Beach, Fla. He was known for the saying "Ooh ooh ooh, Mr. Kotter" as one of the Sweathogs on the show from 1975 to 1979.

Palilillo also appeared in "Laverne and Shirley" and did voices for "Darkwing Duck."