Tributes have flooded in for the late James Gandolfini.

The 'Sopranos' actor unexpectedly passed away from a suspected heart attack while on holiday in Italy with his teenage son, Michael.

Many Hollywood actors have since offered their condolences to the family of the star, who died at the age of just 51.

Writing on Twitter, Samuel L. Jackson said : ''Massive blow to the acting community today ... the passing of James Gandolfini. So talented. My heart goes out to his family.''

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

Meanwhile, Russell Crowe posted on the social media site: ''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.''

Susan Sarandon, who co-starred with James in 2005's 'Romance & Cigarettes', said: ''So sad to lose James Gandolfini.

''One of the sweetest, funniest, most generous actors I've ever worked with. Sending prayers to his family.''

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 ''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.''

Lorraine Bracco, who played Tony's psychiatrist Dr Melfi, said: ''We lost a giant today. I am utterly heartbroken.''