Gandolfini was traveling in Italy on vacation when he fell ill; conflicting reports have him suffering either a heart attack or a stroke. He is survived by his wife, Deborah Lin, and a son, Michael, from a previous marriage.
HBO confirmed his death in a statement: "We're all in shock and feeling immeasurable sadness at the loss of a beloved member of our family. He was a special man, a great talent, but more importantly a gentle and loving person who treated everyone no matter their title or position with equal respect. He touched so many of us over the years with his humor, his warmth, and his humility. Our hearts go out to his wife and family during this terrible time. He will be deeply missed by all of us."
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Gandolfini won three Emmys and one Golden Globe for his performance as Tony Soprano on the acclaimed HBO drama — a complex, sometimes villainous role that launched the current wave of TV antiheroes. "The Sopranos" remains HBO's highest-rated series ever, with 13.4 million viewers tuning in for the Season 4 premiere in 2002.
In addition to "The Sopranos," Gandolfini appeared in dozens of movies, including memorable supporting turns in "True Romance," "Get Shorty," and last year's "Zero Dark Thirty."