The veteran funnyman, who worked with Mel Brooks, Jerry Lewis and Dean Martin, passed away on Thursday (27Jan11) at a care centre in Las Vegas, according to Lvrj.com. No further details were available as WENN went to press.
Callas served in the U.S. army during World War II and later worked as a drummer before turning to stand-up comedy.
He became well-known for his TV appearances, including regular slots on The Tonight Show With Johnny Carson, before he was eventually banned by the host for shoving him in an attempt to generate laughs.
Callas famously voiced dragon Elliot in 1977 Disney film Pete's Dragon and and starred in Robert Wagner's 1970s detective TV show Switch. He also regularly opened for Frank Sinatra at the singer's Las Vegas shows.
He was married to Eve Velac and they were parents to two children.