Multiple sources are reporting that James Gandolfini, the actor best known for his portrayal as Tony Soprano in the HBO series "The Sopranos," has died.

The cause appears to be a heart attack or stroke, details are conflicting.  Variety is quoting sources at HBO who say that Gandolfini was vacationing in Italy at the time.

Although an official notice does not appear on HBO's website as of this writing, a written statement attributed to an HBO spokesperson reads as follows: "We're all in shock and feeling immeasurable sadness at the loss of a beloved member of our family. He was 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 children during this terrible time.  He will be deeply missed by all of us."

The three-time Emmy winner was a native of New Jersey.  He began his acting career relatively late in life, and has since taken roles with lower profiles than organized crime leader Tony Soprano since the series was retired in 2007.

Gandolfini was 51 years old.  He is survived by his wife, Deborah Lin, and two children.

Others remember the man who played Tony Soprano on an HBO website talk forum for "The Sopranos:"

Talk Forum on "The Sopranos" via HBO.com