The Emmy-award winning American actor James Gandolfini, best known for playing New Jersey mafia boss Tony Soprano on the hit television series The Sopranos, has died in Italy aged 51.

Gandolfini's death was confirmed by HBO, the US cable network that produced the Sopranos, which said he was on holiday when he died. HBO spokeswoman Mara Mikialian told Reuters that he died of a possible heart attack.

The actor first came to prominence playing the mob hitman Virgil in the 1993 film True Romance, written by Quentin Tarantino. But he will be best remembered as troubled gangster Soprano who struggled to juggle his family life and his career as a mafia boss over the show's six seasons.

Actor Joseph R Gannascoli, who played Vito on The Sopranos paid tribute last night. He told website TMZ: "James is one guy who never turned his back on me. He was the most humble and gifted actor and person I have ever worked with ... He was a great man and I will forever be indebted to him."

Gandolfini won several awards for his role in The Sopranosthe role, including both the Primetime Emmy Award for Outstanding Lead Actor in a Drama Series and Screen Actors Guild Award for Outstanding Performance by a Male Actor in a Drama Series. He also appeared in the films Zero Dark Thirty, Get Shorty, The Mexican and In The Loop. At the time of his death, Gandolfini had been working on an upcoming new HBO series titled "Criminal Justice.

He 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.