In Legend, Tom Hardy is twice the actor he once was.
The English star, who's already been having a very big, very hardcore year as Mad Max, plays the Kray twins - the sibling gangsters who ruled London's East End for much of the 60s before being sent to jail for much of the rest of their lives.
They were identical twins, says Legend director Brian Hegeland, but divergent characters.
And while the story of Krays has been much canvassed over the years in books and previous films, including 1990's The Krays starring Spandau Ballet's Gary and Martin Kemp, Legeland knew there was still a story to be told - one from an outsider's point of view that wasn't so wrapped up in the Krays' myth which has long portrayed them as doting sons and neighbourhood Robin Hoods in between bits of bovver with the Old Bill.
Tom Hardy features on the cover of this week's TimeOut:
Legend is Hegeland's fifth cinematic feature as director after a 20-year career as a screenwriter whose scripts have included L.A. Confidential and Mystic River.
The first time he heard of the Krays was when he was working on a later-abandoned Led Zeppelin movie in the late 1990s. On tour with a reunited Jimmy Page and Robert Plant, he met one of the band's crew who was missing a finger. The man told Hegeland the Krays had cut it off.
Hegeland learned later that the amputation story was a lie. But he was intrigued that someone would have claimed an association with the gangland pair.
"I think part of the reason it is called Legend is it has gone into the world of mythology about the Krays, he tells TimeOut from California. "And even the people who are very fond of them, none of their stories can be trusted and the couple that really vilify them - none of those stories can be trusted either. One of the things that attracted me about it is that the truth of it is so lost.
"I thought the best way I could get close to that truth was not to forgive them ... but, I thought, to humanise them and make you understand them a bit was the best way I could approach the truth of it."
For that he needed an actor or actors who could pull off both parts - the charming straight rational Reggie and the gay schizophrenic volcanically tempered Ron.
Step forward Tom Hardy who, Hegeland says, only took on Reggie if he could also play troubled Ron.
"Yeah the funny thing was being able to play Ron made it okay for him as an actor to go for that straight down the middle movie star thing that Reggie has.
"He wouldn't have played Reggie if he couldn't play Ron. But he would have played Ron."
"He just needed to be convinced a little bit to play Reggie. Playing opposite himself? It wasn't a hard sell."
Maybe it's a product of the characters he plays but Hardy might seem an intimidating actor to direct.
Hegeland's take?
"Um, you know he's not as long as you have done all your homework and you know what you are talking about. Tom is very serious about what he does. He is very serious about committing himself to film - which is forever. He's the guy on screen and I am very serious about what I do. When Tom has a question you have to have an answer that makes sense to him, which you should have with any actor. Then you are in good shape.
"The irony with Tom was when he was Ron he was very easy. He was almost docile. He would always have his arm around my shoulder and anything you wanted he would say 'yes, absolutely' and he would do it.
"When he was Reggie he was much more stand-offish and wondered 'why are we doing it this way?' You really had to to talk Reggie through everything. He was suspicious and reflected how they were in real life but he is as demanding of you as he is of himself and I will take that every day.
"It was a pleasure to work with him"
Working with Hardy meant working with his regular New Zealand stunt and acting double Jacob Tomuri, who was heavily employed in scenes which had to be shot twice with Hardy alternating roles.
"You know [Jacob] is the unsung hero of the film and I have told him that many times. He had an incredibly difficult job to do and basically then not appear in the film."
"I felt if we were to make this work we needed to take on the continuity," says Tomuri.
"So when you watch the film you can lose the fact that one actor is playing two roles. I wanted to make sure that I was on point with everything - with Tom and the other cast members - with what I was doing, so the audience couldn't let go.
"Not only was the accent important to nail, but I wanted to replicate Tom's characters as much as possible, from their posture to their mannerisms.
"On Mad Max we invited the actors into the stunt world whereas with Legend I was in Tom's world which is the acting domain. I was out of my comfort zone to a degree.
"I took it on board to do the accent and replicate Tom's characters as much as possible. It was also good for the other actors so they could continue to interact with Tom rather than just a tennis ball on a stick."
Movies have been made featuring one actor playing lookalikes since the development of split-screen technology in the pre-digital era.
"The technology hasn't changed a lot since The Parent Trap with Hayley Mills," laughs Hegeland, who says he started to get nervous looking at old double-act films after he had cast Hardy in both roles.
Fortunately, the Krays were different sides of a very bent coin and by the time they were adults they had started looking different. That also meant any scene involving both Krays had to be shot twice - with a hair and make-up change for Hardy in the middle.
The most impressive shot, however, involves just Reggie and his eventual wife Frances (Emily Browning), through whose eyes much of the story is told.
It's a single-take steadycam shot which shows the pair entering a posh club owned by the Krays and Reggie balancing taking care of his date and taking care of business. Of course, it's something of a Goodfellas homage.
But Hegeland says Legend gave him a chance to make a gangster movie that wasn't repeating what had gone before.
"Yeah I've wanted to do one for a long time and as far as doing an Italian mafia film, I wouldn't even attempt it because it's just pointless with what we'd be compared to, even on television. It's just pointless.
"But doing a British one got me one step removed from all that."
Who: Brian Hegeland (pictured) directing Tom Hardy
What: Legend, a new film about the notorious Kray twins
When and where: Opens at cinemas next Thursday
• Additional reporting Dan Ahwa
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