Tributes have poured in for James Gandolfini, the American actor best known for his role as the mob boss in The Sopranos, who died on Wednesday at the age of 51.

James died on holiday in Rome, according to the HBO TV network and his managers Mark Armstrong and Nancy Sanders.

It is understood he was in the country to attend the 59th Taormina Film Festival, and he is believed to have died from a suspected heart attack.

“Our hearts are shattered and we will miss him deeply,” his managers said.

In a statement HBO called him 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’.

James played Tony Soprano in the groundbreaking series that aired from 1999 to 2007, winning three Emmy awards and a Golden Globe for his portrayal of the conflicted mob boss who was both brutal and emotionally delicate.

The Sopranos creator David Chase described him as ‘a genius’.

Tributes to James came from Hollywood’s biggest stars and beyond. Actor Michael J Fox wrote on Twitter: “Shocked and saddened by James Gandolfini’s passing. My deepest sympathies to his family and friends,” while actress Lindsay Lohan wrote: “James Gandolfini was a dear friend and a great man. My heart goes out to his family. He will be greatly missed.”

Comedian Robin Williams wrote on Twitter: “My thoughts and prayers go out to James Gandolfini’s family. An extraordinary actor,” while actress Mia Farrow said: “Awful awful news. James Gandolfini will be missed. He was a great actor.”

Oscar winner Susan Sarandon tweeted: “So sad to lose James Gandolfini. One of the sweetest, funniest, most generous actors I’ve ever worked with.”

James’s performance as Tony Soprano was indelible and career-making, but he refused to be stereotyped as the bulky mobster who was a therapy patient, family man and cold-blooded killer.

After the series concluded, James’s varied film work also took in comedy, with Armando Ianucci’s political satire In The Loop, and voiceover as the Wild Thing Carol in Where the Wild Things Are. His film credits included Zero Dark Thirty and Killing Them Softly, and he also shared a Broadway stage in 2009 with Jeff Daniels, Hope Davis and Marcia Gay Harden in the celebrated production of God Of Carnage, for which he earned a Tony Award nomination for best actor.