James Gandolfini, the actor who famously played Tony Soprano on "The Sopranos," died of a suspected heart attack today in Italy.

He was 51.

Gandolfini was travelling in Rome, where he was on vacation and was scheduled to attend the Taormina Film Fest.

In a statement, HBO called the actor a “great talent” and a “gentle and loving person.”

“We're all in shock and feeling immeasurable sadness at the loss of a beloved member of our family,” HBO said in a statement. “He touched so many of us over the years with his humor, his warmth and his humility … He will be deeply missed by all of us.”

The New Jersey-raised actor rocketed to popularity for his critically-acclaimed portrayal of the tough-talking mob boss who had some personal issues to work out on HBO’s hit show.

Gandolfini won three Emmy Awards for Best Actor in a Drama and eventually earned $1 million per episode.

Fearing he would forever be typecast as a gangster from New Jersey, Gandolfini was originally hesitant to take the role, according to Rob Salem, TV critic with the Toronto Star.

“But because he was such a competent actor -- the sensitivity and dimension that he brought to that role -- he could play the evilness of Tony Soprano,” Salem told CTV’s News Channel.

“That was a real tightrope to walk: make that character relatable as a human being … and also not diminish the totally evil, horrible guy he was. He walked that line, often brilliantly.”

But Gandolfini couldn’t have been more different than the character he embodied so well on the small screen, according to Salem.

“Painfully, painfully shy,” Salem said. “You’d see him at a press conference and you could just tell it was like having dental surgery for him. He just hated talking about his work, hated talking about himself. You were lucky to get a monosyllable out of him.”

Away from the cameras, he was anything but a mobster. In fact, he was just the “sweetest, nicest guy,” Salem said. “Very unassuming, very matter of fact. Very, very humble.”

Gandolfini first found fame in 1992 when he landed a role in a Broadway version of "A Streetcar Named Desire" alongside Alec Baldwin and Jessica Lange.

Shortly after, he went on to play a hitman in the 1993 movie "True Romance."

Some of his other film credits include "Zero Dark Thirty," "The Mexican" and "Get Shorty."

If you don’t remember seeing Gandolfini in those movies, that’s actually a credit to the actor’s ability to “disappear,” said Salem.

“He was in so many movies you wouldn’t know he was in because he disappeared,” Salem said, adding that the actor was often unrecognizable.

Though Gandolfini grew up in New Jersey, he always had a strong sense of his heritage: his father, born in Morgotaro, Italy, and his mother, who grew up in Naples, Italy, were both devout Roman Catholics and spoke Italian at home.

As a result, he visited Italy regularly.

Before his death, Gandolfini was in the midst of a career revival, according to Salem.

In 2011, he executive produced an HBO film about Ernest Hemingway called “Hemingway & Gellhorn.”

He also starred in a crime drama called “Animal Rescue” alongside actors Tom Hardy and Noomi Rapace. The film is set to be released in 2014.

“We’ll never get to see where that (new career direction) would have taken him,” said Salem.

Gandolfini is survived by his wife, Deborah Lin; his daughter, Liliana, born last October; and a teenage son, Michael, from his previous marriage to March Wudarski.