James Gandolfini, the star of HBO's groundbreaking TV series "The Sopranos," died Thursday while vacationing in Italy, TMZ reported. He was 51.

Gandolfini died after suffering a massive heart attack, TMZ said, citing sources it did not identify.

HBO said Gandolfini was vacationing, Daily Variety reported. TMZ said he was in Italy to attend the 59th Taormina Film Festival and had been scheduled to participate in the festival this weekend.

Gandolfini, who won three Emmy Awards for best actor for his portrayal of neurotic mob figure Tony Soprano, was nominated for a Tony for best actor in 2009 for his performance in "God of Carnage."

His film credits include "Crimson Tide," "Get Shorty," "Where the Wild Things Are" and "Zero Dark Thirty," and a television production of "12 Angry Men."

Gandolfini, a native of Westwood, N.J., is survived by his wife, Deborah Lin, and their daughter, Liliana Ruth, born in October, as well as a son from a previous marriage.