LOS ANGELES-- Comedic legend Don Rickles passed away at his home in Los Angeles on Thursday, his publicist announced. He was 90 years old. Multiple sources report Rickles died of kidney failure with his wife by his side. Often called "Mr. Warmth," was a frequent guest of late-night TV shows, beginning in the 1960s. He made his first appearance on The Tonight Show Starring Johnny Carson. Even at 90, he was doing interviews on The Tonight Show Starring Jimmy Fallon.