French actor Vincent Cassel may have a short temper, but he's not a dangerous guy -- at least off-screen.

His father, famous French thespian Jean-Pierre Cassel, was known as a "charmer" and nice guy on-screen. So to distinguish himself, the son opted to play tough and violent characters. His latest role is certainly both.

Playing infamous French gangster Jacques Mesrine in the two-part epic "Mesrine: Killer Instinct" and "Mesrine: Public Enemy No. 1," opening in Minneapolis on Sept. 3 and 10, respectively, Cassel showcases both his dangerous side and his leading-man charisma.

Cassel, 43, has been a leading man in France, but in American films he is often typecast as a villain, in the likes of "Ocean's 12," "Eastern Promises" and the upcoming "Black Swan."

He played a young hood in the film that gave him his first big break -- the 1995 French crime drama "La Haine." But art-film lovers may remember his haunting performance in 2002's controversial "Irreversible" as a man seeking revenge for the rape of his girlfriend, played by his real-life wife, Italian actress Monica Bellucci ("Matrix Reloaded").

Speaking by phone from Los Angeles, Cassel said he knew about Mesrine as a teenager: "I remembered hearing his name on TV but I didn't even know he was a gangster. It wasn't until they had his body exposed on prime-time news that I understood more about him."

The films span three decades, starting in the late 1950s when Mesrine was a young soldier in the Algerian War, to the beginnings of his criminal life, to becoming Public Enemy No. 1 in France and lastly, his death in Paris in 1979.

It's been about seven years since Cassel was first contacted for the role. During that time he read the gangster's autobiography, "Death Instinct," along with some articles that had never been published. He also met people who had spent time with Mesrine.

"The good thing about the film taking so long to put together was I had time to get into it, then forget about it, come back to it and have new things to digest," Cassel said.

Both films were shot over a nine-month period. To play Mesrine in his later years, Cassel gained 45 pounds -- something he laughs off as "a pregnancy."

"The timing was perfect for me as an actor to do a heavy transformation once in my life, something like 'Raging Bull,' and I didn't want to use any prosthetics."

The performance won Cassel a best-actor Cesar (the French Oscar) while director Jean-François Richet, probably best known for directing 2005's remake of "Assault on Precinct 13," also nabbed an award.

Although he's quick to dismiss the suggestion that Mesrine was his biggest challenge as an actor, Cassel takes satisfaction in the fact that the films are getting distributed worldwide and that American audiences will see him in a leading role.

"Jean-François and I would do a debriefing after shooting each night and almost every time we'd end the conversation by saying, 'Can you imagine how lucky we are making this movie?'"