Black Mass trailer: Johnny Depp and Benedict Cumberbatch star in biopic of notorious gangster Whitey Bulger

The film also features Sienna Miller Kevin Bacon

Johnny Depp and Benedict Cumberbatch in Black Mass (YouTube/Warner Bros.)

The dramatic trailer showcasing Johnny Depp’s latest foray onto the big screen has dropped, and shows the Hollywood actor playing a notorious - and balding – Boston gangster in Black Mass.

The biopic tells the story of Whitey Bulger, who became an FBI informant to take down an Italian mob – in turn making him the most hard nosed gangsters in the city’s history.

Black Mass’ star-studded cast also features Benedict Cumberbatch (Imitation Game), Kevin Bacon (Footloose), Sienna Miller (Layercake), Dakota Johnson (50 Shades of Grey) and Joel Edgerton (Warrior ).

The clip starts with a misleadingly friendly chat over dinner, as Bulger asks his host how he prepared the steak.

When he playfully replies that “It’s a family secret”, Bulger presses him.

Caving in, the host proudly tells him it’s “ground garlic with a little bit of soy”.

But the scene becomes tense when Depp replies: “I thought it was a family secret.”

“You said this was a family secret, and you gave it up to me – boom,” Bulger says, as a montage of his dodgy dealings plays as he sternly explains that spilling a secret landed him in jail.

Black Mass will open in cinemas on the 25th September.