Tony played Paulie "Walnuts" Gualtieri, one of Tony Soprano's main guys for every season of the HBO hit show. His brother Robert announced his passing on Facebook saying "It is with great sadness, but with incredible pride, love and a whole lot of fond memories, that the family of Gennaro Anthony "Tony" Sirico wishes to inform you of his death."

Robert says Tony passed Friday morning. Sources connected to the family tell us Tony had been living in an assisted living home in Fort Lauderdale, FL for a couple years, and had been in failing health.

Of course, Tony will be most remembered for his 'Sopranos' role -- he won 2 Screen Actors Guild Awards for Outstanding Performance by an Ensemble Cast.

Fun fact: He'd actually auditioned for the role of Tony Soprano's Uncle Junior -- which, of course, ultimately went to Dominic Chianese. Instead, David Chase gave him the Paulie role. He had one rule about his acting gigs ... he never played "rats."

He also got a lot of voice acting roles on animated hits like "Family Guy" and "American Dad" -- and played a mobster or gangster in tons of movies, including "Goodfellas," "Mighty Aphrodite," "Gotti," "Cop Land" and "Mickey Blue Eyes."

Sirico was a big supporter of the U.S. military -- he and James Gandolfini once traveled to Iraq for a rally for the troops there. He continued to support the Wounded Warrior Project organization too.

He's survived by his 2 children, Joanne and Richard, several grandchildren and his siblings.

Tony was 79.