In Legend, Tom Hardy plays real-life identical twins and infamous London gangsters Ronald and Reginald Kray. It was a role originally intended for two different actors, writer-director Brian Helgeland tells Yahoo Movies. But after one dinner, Hardy convinced the filmmaker, telling him he needed to play both parts.

The Kray twins ran the East End during the height of the swinging '60s. In spite of their many crimes — including armed robberies, arson, and even murder — the twins became celebrities, hanging out with the likes of Frank Sinatra and Judy Garland.

As you can see in the exclusive first stateside trailer above, Hardy effortlessly plays the dual roles. But how he did it is a little more complex. Luckily Helgeland, who won an Oscar for co-writing the screenplay for L.A. Confidential (1997), phoned us up to explain how his leading man juggled two very different roles and managed to fight himself:

Tom Hardy can bring this unique dimension to misguided, even evil characters — in films like Bronson, The Dark Knight Rises, and now in Legend. Why do you think this is?

He’s really a true actor. He’s looking for the part to play. Most movie stars have a persona. You get the same guy over and over again, it’s a comfort zone. They figure out what it is their audience wants to see out of them and deliver it. That’s what makes a movie star in a lot of ways. Tom, I don’t think, has an interest in that. He’s all about the character. There are these wild swings in what he does. He’s very much a chameleon, never plays the same guy twice. That makes him hard to pin down. … Even when he’s a protagonist, it’s a character performance he’s looking to do, really.

The irony in that is I got the best of both worlds because of the character of Ron Kray is, in the world of crime, one of the great characters of all time. He’s so outrageous. Because [Tom] got to play Ron, it made it OK for him to play Reggie who’s much straighter. What was exciting for me was I wanted Reggie, on the surface, to be more of a classic leading man movie star, which Tom is not really interested in playing that. But in this case he played it because it’s a counterpoint to the other brother. He was handsome and dashing, and all those things he generally avoids.

And he can fight.

He’s very serious about that stuff. I am, too, but not to the degree he is. I think the physicality of a character is part of how he expresses who the character is, so he doesn’t want to end up in some generic fight scene. Both brothers have their own style in approaching violence. That’s as important to him as bringing the person to life as anything else that he has to do.

We went through weeks and weeks of rehearsals to get a move down so it could be played for real when we were going at it. There’s a scene where he fights himself, or the brothers fight, I should say. His stuntman Jacob Tomuri — they know each other from Mad Max: Fury Road — that morning when we were going to roll, Tom came up to me and asked, “How many takes do you think you’re going to do?” Which he never asked me ever. I said, “Why you want to know?” He said, “Well, because we’re going to be really hitting each other. [laughs] So I need to know so we can pace ourselves.” I said, “In that case I would say three takes.” He goes, “Oh good! Three takes we can go for it on each take.” It was three takes and they really hit each other. I’m terrified Tom’s going to have his nose broken in the middle of a take.

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