Hollywood has paid tribute to James Gandolfini.

'The Sopranos' star passed away suddenly of a heart attack while on holiday in Italy with his son, Michael, and tributes from many of his contemporaries have since been flooding in.

Russell Crowe posted on Twitter: ''Sad to hear about James Gandolfini. First met Jimmy back in '94. He was roommates in NY with Lenny Loftin. Lovely man. RIP Jimmy (sic)''

Rose McGowan tweeted a picture of her and James in front of a US flag, adding: ''I am heartbroken about James Gandolfini. He was a gentle giant and great man. I love this picture, I loved him.''

Michael J Fox tweeted: ''Shocked and saddened by James Gandolfini's passing. My deepest sympathies to his family and friends.''

Some of the most poignant tributes have come from James' co-stars in 'The Sopranos' - in which he played lead character Tony Soprano from 1999 to 2007 - and was the role which made him.

Joe Gannascoli, who played Vito Spatafore in the series said his co-star was ''way too young''.

He added to TMZ.com: ''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 ... and I will forever be indebted to him.''

Edie Falco, who played Carmela Soprano, the wife of James Mob boss character Tony Soprano, said she was ''shocked and devastated'' by his passing.

She added: ''He was a man of tremendous depth and sensitivity, with a kindness and generosity beyond words. I consider myself very lucky to have spent 10 years as his close colleague.''