James Gandolfini, the US actor best known for his role as a therapy-seeking mob boss in The Sopranos, has died at the age of 51.

Gandolfini suffered a possible heart attack while on holiday in Rome, the US HBO TV network told the BBC.

According to TMZ website, New Jersey-born Gandolfini went to Italy to attend a film festival in Sicily.

He won three Emmy awards for his role as Tony Soprano, a mafia boss juggling his criminal career and family life.

"It is with immense sorrow that we report our client James Gandolfini passed away today while on holiday in Rome, Italy," said his managers, Mark Armstrong and Nancy Sanders, in a statement on Wednesday night.

"Our hearts are shattered and we will miss him deeply."

HBO also said the star of The Sopranos, which ran for six series on the cable channel from 1999-2007, would be "deeply missed".