Sirico’s death was announced earlier Friday in social media posts by family and friends close to the actor. A New York City native, Sirico, 79, was best known for his portrayal of Italian gangsters, notably a role on the legendary HBO crime drama The Sopranos.

Michael Imperioli, who played Christopher Moltisanti on the iconic show, said in an Instagram post Friday that he was “heartbroken” by Sirico’s death, calling the actor “truly irreplaceable.”

“Tony was like no one else: he was as tough, as loyal and as big hearted as anyone i’ve ever known,” Imperioli said in the post. “I was at his side through so much: through good times and bad. But mostly good. And we had a lot of laughs. We found a groove as Christopher and Paulie and I am proud to say I did a lot of my best and most fun work with my dear pal Tony. I will miss him forever.”

After acting in several Woody Allen films and gangster movies, including the 1990 movie Goodfellas, Sirico came into his best-known role in the critically acclaimed Sopranos, which premiered in 1999 and lasted six seasons.

Sirico played Peter Paul “Paulie Walnuts” Gualtieri, a hard-bitten tough-guy enforcer of mob boss Tony Soprano, mastered by the late James Gandolfini. Sirico said in a 2001 interview with Cigar Aficionado that he drew on his experience watching “mob-type people” while growing up in the Bensonhurst section of Brooklyn, saying “it was a miracle that I didn’t wind up like them.”

Twitter lit up with remembrances of Sirico, including his cameo on Sesame Street and role on Family Guy.

Comedian Kevin Banner wrote in a tweet: “His portrayal of Paulie Walnuts on the Sopranos was one of the greatest things in the history of tv.”

“As someone who just got to fall in love with THE SOPRANOS this year, I’m not ready to say goodbye to Paulie Walnuts,” Heather Wixson, managing editor of Daily Dead News, wrote in a tweet. “I knew Tony Sirico from a ton of other stuff but it was Paulie where I totally connected with Sirico big time. His bit on Family Guy is an all-timer too. RIP sir.”

“One of the most vivid memories I have is of Tony Sirico swaggering toward me with a couple of big guys around him. “Hey, you … I like YOU.” He seemed to love the odd cards life dealt him,” political commentator Keith Olbermann wrote in a tweet.

Robert Sirico, Tony Sirico’s brother, said in a Facebook post that the actor is “survived by his two beloved children, Joanne Sirico Bello and Richard Sirico, grandchildren, siblings, nieces, nephews and many other relatives.”

Twitter user @JakeElman97 wrote in a tweet that he hoped Sirico and Gandolfini “are hunting interior decorators in the next life,” a reference to a well-liked episode of the show.

Newsweek has reached out to Sirico’s agent for comment.