John Travolta - John Travolta Mourning Loss Of Former Welcome Back, Kotter Co-star

The actor passed away of an apparent heart attack at his Palm Beach Gardens home in Florida on Tuesday morning (14Aug12), aged 63.

His sudden death prompted many fans of the hit U.S. sitcom, in which Palillo played nerdy high school student Arnold Horshack, to recall their love for the series online, and now Travolta, who shared the small screen with the star for five years, has paid tribute to his late pal.

A statement from the Saturday Night Fever star reads, "Ron was a wonderful person and talent. And helped catapult Welcome Back, Kotter to great success. We will miss him."

Palillo is the second star of the popular programme to die this year (12) - Robert Hegyes, who played tough guy Juan Epstein, passed away in January (12).