Director Scott Cooper's crime drama screened out of competition at the annual Italian festival on Friday (04Sep15), and reviewers were quick to show their support for the movie by giving it a double round of applause as the end credits rolled.

Many have hailed Depp's role as Bulger as one of his best performances to date, with The Hollywood Reporter's Todd MCCarthy claiming the actor "shines" as the Boston kingpin, hailing his portrayal "charismatic... fully convincing and frightening".

Variety's Scott Foundas insists Depp's performance is "mesmerising", showing the actor at his "career-best" after film flops like Mortdecai and The Lone Ranger, while co-star Joel Edgerton has also won high praise for his role as FBI agent John Connolly.

Addressing reporters after the screening, Depp, 52, admitted he embraced his dark side for the part, saying, "I found the evil in myself a long time ago, and I've accepted it. We're old friends."

The former teen heartthrob adds to The Associated Press, "I've always wanted to try to be a character actor, more than the poster boy that they tried to make me, about 100 years ago.

"I find great safety but at the same time danger in trying to do these transformations... I think that's important also as an actor, to test yourself, challenge yourself each time. Take the chance that you may actually fall flat on your face and look like a complete a**."

Black Mass, which also stars Benedict Cumberbatch, Kevin Bacon and Dakota Johnson, is based on the bestselling 2001 book Black Mass: The True Story Of An Unholy Alliance Between The FBI And The Irish Mob, which was written by DICk Lehr and Gerry O'Neill.

Sienna Miller's brief appearance as Catherine Greig, one of Bulger's girlfriends, was cut from the film after Cooper decided her storyline didn't fit into the movie.