I guess it’s official. He was rumored to be joining the cast of the film, but there’s our first official confirmation of it, courtesy of Variety, earlier today.

Anthony Mackie has joined the cast of the Warner Bros. period police drama ”Gangster Squad, which already includes a rather strong list of actors including Sean Penn, Ryan Gosling, Josh Brolin and Michael Pena.

Gangster Squad, which takes place in the 1940s, is based on a multi-part LA Times article by Paul Lieberman – a true story about the LAPD’s secret squad of mercenary cops assigned to hunt down infamous gangster Mickey Cohen, a member of the Jewish Mafia, who also once worked for Meyer Lansky and Bugsy Siegel, all in an effort to keep East Coast organized crime figures from moving and settling in.

Mackie will play former LAPD lieutenant Rocky Washington.

I haven’t read the LA Times piece the film will be based on, so I can’t say much about the lieutenant; and a Google search didn’t immediately return anything. But I’ll keep digging.