James Gandolfini, best known for his role as an anxiety-ridden mob boss on HBO's "The Sopranos," died Wednesday while on vacation in Italy. He was 51.
The exact cause of death is not known, but his managers said it was possibly a heart attack.
"It is with immense sorrow that we report our client, James Gandolfini. passed away today while on holiday in Rome, Italy," managers Mark Armstrong and Nancy Sanders said in a joint statement. "Our hearts are shattered and we will miss him deeply. He and his family were part of our family for many years and we are all grieving."
The actor had been scheduled to make an appearance at the Taormina Film Fest in Sicily this week.
Gandolfini won three Emmy Awards for his portrayal of Tony Soprano, the angst-wracked mob boss who visited a therapist and took Prozac while knocking off people. "The Sopranos" aired from 1999 to 2007.
Gandolfini's acting credits included roles in "The Last Castle" with Robert Redford, "The Mexican" with Brad Pitt and Julia Roberts and "Surviving Christmas" with Ben Affleck.
In recent years, he had starred in several movies, including the Oscar-nominated "Zero Dark Thirty," "The Taking of Pelham 1 2 3" and "Killing Them Softly."
Gandolfini was also known to children, voicing Carol, a wild thing, in the 2009 movie adaptation of Maurice Sendak's classic "Where the Wild Things Are."
He took to the stage to do a reading of Sendak's "In The Night Kitchen" to mark the author's 80th birthday.
News of the actor's death spread quickly, drawing shock and sadness from those who had worked with him.
"James Gandolfini was a kind, funny, wonderful guy. I'm so lucky to have worked with him. Sending love to his family. Such a sad, sad day," Olivia Wilde, who starred with the actor in "The Incredible Burt Wonderstone," said in a post on Twitter.
Actor Steve Carell, who also appeared in the movie, simply said on Twitter: "James Gandolfini. What a great loss."
New Jersey Gov. Chris Christie described himself as a "huge fan" of Gandolfini.
"It's an awful shock. James Gandolfini was a fine actor, a Rutgers alum and a true Jersey guy," he said.
Gandolfini is survived by his wife, Deborah, and their 9-month-old daughter, Liliana. He is also survived by a son, Michael, from another marriage.