James Gandolfini -- who famously played Tony Soprano on "The Sopranos" -- died earlier today in Italy ... TMZ has learned.
Gandolfini is believed to have suffered a heart attack. He was 51.
Gandolfini was in Italy to attend the 59th Taormina Film Festival in Sicily -- and he was scheduled to participate in a festival event this weekend with Italian director Gabriele Muccino.
Gandolfini shot to fame playing a hitman in the 1993 hit "True Romance" ... and quickly became a Hollywood legend when he was cast as Tony Soprano in 1999. He won 3 Emmy awards for the role during the show's 6 season run.
Gandolfini also appeared in a ton of huge movies including "Get Shorty," "The Mexican" and "Zero Dark Thirty."
We last spoke to Gandolfini last month in L.A. -- he was in great spirits, making funny faces and joking about a "Sopranos" movie.
Gandolfini is survived by his wife Deborah Lin, who gave birth to the couple's daughter in October 2012. He also has a teenage son from a previous marriage.