To say Don Rickles was a Las Vegas regular would be a colossal understatement. He started in 1959 and was still working as a headliner at the age of 90.

Rickles, who would have turned 91 on May 8, died Thursday of kidney failure. He was scheduled to perform at The Smith Center for the Performing Arts on April 21.

He played a serious role as a casino manager who worked with Robert Di Niro’s character in the mob classic, “Casino,” which was primarily filmed in Las Vegas in 1994.

For most of a decade, starting in 1974, he was a fixture on Dean Martin’s celebrity roasts when the show was held at the MGM Grand Ziegfeld Room. Local roasters included Buddy Hackett, Wayne Newton, Joey Bishop, Jimmie Walker and Rich Little, who later moved here.

Prop comic Carrot Top was in the 1998 movie “Dennis the Menace Strikes Again” with Rickles. Carrot Top played Sylvester, a con artist who sold a youth potion to Rickles’ character, Mr. Wilson, the long-suffering neighbor of Dennis (Justin Cooper). When the potion proves to be bogus, Dennis and Mr. Wilson team up against the swindlers.

Carrot Top said Rickles showed up on the set grumpy in the mornings.

“He’d bust my balls every day,” he said. “That was in the morning. Then, after that, he’d be the sweetest man in the afternoon.”

Carrot Top, whose real name is Scott Thompson, spotted Rickles at Craig’s, a celebrity hangout in Beverly Hills, earlier this year.

“He was with his agent and wife. Florence Henderson walked by, then Larry King and Nikki Sixx of Motley Crue.”

Carrot Top approached Rickles’ table with trepidation and introduced himself.

“We saw you coming from Hollywood,” said Rickles, referring to Thompson’s trademark mop of orange hair.

“I’ve tried to forget everything I’ve done with you,” jabbed Rickles, known as Mr. Warmth and The Merchant of Venom.

One day on the set, Carrot Top dropped a popular curse word that starts with s.

“He came over during a break and said, ‘You never curse on the movie set.’ Then, he goes into a rant with all of his off-color humor that’s worse than anything I said,” said Thompson. “He was a really sweet man with a really big heart.”

Celebrity tributes poured in Thursday: Mel Brooks: “Don Rickles. One of the bravest, funniest and sweetest guys that ever performed. A dear pal that we will all sorely miss.”

Tom Hanks: “A God died today. Don Rickles, we do not want to lose you. Never. Hanx.”

Stephen Colbert: “Don Rickles hugged me once. It’s all downhill from there. God bless you, Rickles.”

Jimmy Kimmel: “90 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.”

Penn Jillette: “Hockey puck. We've lost ‪@DonRickles I love him so. Smart, funny, a pro and most important deeply and honestly kind. Kind is what matters.”

Lewis Black: “Don Rickles was a cyclone of funny with a heart of gold. Is God ready for your maniacal wit? Would love to hear what you said on arrival.”

Jim Norton: “One of the funniest, ballsiest comics of all time. RIP Don Rickles.”

Kevin Pollak: “Don Rickles created a style of stand up and owned (!!!) it his entire career of 60-plus years. It's unparalleled. No, I mean, NO ONE did that.”

Kevin Nealon: “As I was nearby, #DonRickles once whispered in my wife’s ear, ‘What are you doing with a loser like him?’ I was honored. #rip #sad”

Fred Willard: “So sad to lose Don. He made me laugh harder & longer than anyone. He was the reason to go to Las Vegas, to watch a talk show. A legend.”

On this day… April 7, 2007: “The Hoax,” starring Richard Gere as con artist Clifford Irving, opens this week to good reviews and poor business. It recounts Irving’s bogus 1971 “autobiography” of Howard Hughes, who emerged from years of seclusion from his hotel, the Desert Inn, to denounce the book and expose the scandal.

Sightings Country star Chris Stapleton, arriving at La Comida Mexican restaurant after the Academy of Country Music Awards with so much security “it looked like ‘Men in Black,’” said a spy…

Sports broadcasting legend Brent Musburger, touring the Mob Museum on Wednesday with his wife. He is featured in the latest Sports Illustrated for his role in the newly launched Vegas Stats & Information Network…

ESPN anchor Max Bretos, wearing a Carrot Top-like wig under a New York Mets cap at the end of his SportsCenter segment on Wednesday…

Former Boston Red Sox slugger Moe Vaughn, dining at Lavo Italian Restaurant (Palazzo) on Tuesday.

The punch line “The Cleveland Zoo announced today that its rare black rhinoceros is pregnant. They made the announcement right after she confirmed it with her rhino-cologist.” — Seth Meyers.