The comedian's fans, friends and peers have been posting tributes on social media.
Don Rickles' fans, friends and peers have been expressing their condolences after hearing news of the comedian's death.
ET confirmed that Rickles died on Thursday morning in his Los Angeles home from kidney failure. He was 90.
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Rickles' impact on the comedy and entertainment industry was certainly felt as celebrities have been posting tributes to the late comedian since learning of his death. Here's a look at what the stars are sharing in remembrance of Rickles:
Bob and Ginnie Newhart: "He was called 'The Merchant of Venom,' but in truth, he was one of the kindest, caring and most sensitive human beings we have ever known. We are devastated and our world will never be the same. We were totally unprepared for this."
Martin Scorsese: "Don Rickles was a giant, a legend… and I can hear his voice now, skewering me for being so lofty. I had the honor of working with him on my picture Casino. He was a professional. He kept me doubled over with laughter every day on the set - yet he was a complete pro. We became friends over the years and I had the honor of being roasted by him more than once - sometimes when I didn’t expect it. He just started showing up at places and insulting me. Experiencing Don, and tuning into his mind, I witnessed the evolution of his comedy. It was like listening to a great jazz musician wail. Nobody else did what he did. He made comedy into an art form. And like all geniuses, comic or otherwise, he’s irreplaceable. He was much loved. I’m really missing this man."
Jim Carrey: "Don once begged me for a couple of bucks then told me to twist myself into a pretzel. Ego slayer! Comic Everest! Spank you, Mr Rickles."
Tim Allen: "Don Rickles is one of the biggest reasons I am a comic today. I feel bad, mostly for everyone in Heaven who will now learn first hand from the sharpest wits ever, what it's like to be Rickled."
Amy Schumer: "RIP Don."
Jimmy Kimmel: "Ninety years with Don Rickles weren't enough. One of the sweetest and most lovely people I had the pleasure of knowing. We miss you already."
Tom Hanks: "A God died today. Don Rickles, we did not want to ever lose you. Never."
Barbra Streisand: "Being skewered by Don Rickles was side-splitting funny. A gentle soul with rapid fire wit."
Billy Crystal: "Don Rickles has passed away. A giant loss."
Andy Richter: "RIP to this sweet and lovely man."
Patton Oswalt: "In lieu of flowers, Don Rickles' family has requested that people drop their pants and fire a rocket."
Billy Eichner: "RIP Don Rickles. One of the funniest people that ever lived, you dumb schmuck."
Jay Mohr: "Don Rickles, JFK/LAX we spoke for three hours while his beautiful wife Barbara slept. Don Rickles was so kind to me, I forgot we'd never met. LOVE."
Al Roker: "The Merchant Of Venom, legendary comedian @DonRickles passed away at 90. I just interviewed him. The sweetest guy, great hubby and dad."
Jim Gaffigan: "RIP Don Rickles. Legend."
Jim Norton: "One of the funniest, ballsiest comics of all time. RIP Don Rickles."
George Takei: "Don Rickles, you kept us laughing for so many years. We will miss you dearly. Thanks for the zingers. You were one of a kind."
Carol Channing: "He was an original, with a unique flair for comedy that was all his own. He will be missed."
Suzanne Somers: "I came into the nightclub business at the tail end of the golden era of the Rat Pack. I got to know them all, and in the last couple of decades, Alan and I became great friends with Don and his wife, Barbara. They came to our house for dinners, we went to his birthday party every year. I’ve sung to him, sat on his lap , let him make fun of me and it was all fun and a privilege. I feel blessed to have had him as a friend and both Alan and I will miss him forever. Now he is with my other great friends, Merv Griffin, Frank, Sammy. RIP dear Don. Such a loss to us all."
Rich Little: "Having done 24 Dean Martin roasts, I know without a doubt that Don Rickles was the greatest comedian of all time. There were few, if any, that were quicker than Don. He didn't think of the next line he would use, he was already thinking of the line after that. There were many times on the roast that I literally fell out of my chair laughing. In private life, Don was a very nice man. There will never be another man like him."
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Rickles is survived by his wife of 52 years, Barbara, as well as his daughter and a son, along with two grandchildren.