The actor grew famous for his character Horshack's catchphrase of "Ooh! Ooh! Ooh!" (Doctor Free/Flickr)

Palillo's agent, Scott Stander, confirmed the news. 

TMZ reported the actor's death was unexpected. He appeared to be in good health, but was a heavy smoker. He had been suffering from a severe cough and had a doctor's appointment scheduled Tuesday.

CNN reported the actor was most famous for his roll as Arnold Horshack in "Welcome Back, Kotter," which followed a group of remedial students at a Brooklyn high school. The show also starred John Travolta. He was also well-known for Horshack's catchphrase of "Ooh ooh! Ooh!"

Palillo also appeared on the short-lived comedy "Ellen" and made an appearance on "Celebrity Boxing," where he was defeated by "Saved by the Bell" actor Dustin Diamond.

Most recently, the actor taught acting for film and camera to teenagers at a charter school for the arts.

Read the full story at CNN and TMZ.

Reach Supervising Executive Producer Amanda Martinez here.