Tom's Hardy as nails dual role

One of the favourites is Tom Hardy, but the 37-year-old insists it's all hearsay, "myths circulated by people who don't know what's going on", he remarks, rubbing his beard.

Asked if the role interests him, he crosses his tattooed arms and says: "I think a question like that is certain death for anybody who would be interested in playing that part. So I don't know whether to say yes or no to it...

"I wouldn't say no," he adds after a slight pause. "There's been no serious conversation."

The actor, who's battled addiction and dropped out of the Drama Centre London after landing his debut role in TV mini-series Band Of Brothers , received acclaim for his portrayal of the notorious inmate Charles Bronson, in 2008 movie Bronson.

He's since brought to life the villainous Bane in 2012's The Dark Knight Rises and the tormented title character in this year's Mad Max: Fury Road, earning a reputation for being as intense in interviews as he is on screen.

But he thinks his description as a 'Hollywood hard man' is "nonsense".

"Do you know what I think? If you play the bass in the band, you play the bass in the band, but I can drum too," he offers, in an East End accent that belies his roots in leafy south-west London, where he grew up the only child of artistic, literary parents.

He can also lip-sync, as proven in the viral videos of him miming along to the likes of Whitney Houston and 50 Cent.

"Yeah, I'm pretty good at that," Hardy agrees, grinning. "I'm a bit of a Dubsmash man," he adds, referring to the popular app.

No doubt he wishes he could lip-sync his way through Rocketman, the new Elton John biopic he's attached to, having admitted in the past that "I'm not a singer - I have no idea".

His chirpy and chatty demeanour today might have something to do with becoming a dad again (he already has a son from a previous relationship), as his wife, the actress Charlotte Riley, is expecting. (In fact, hours after our interview, she debuted her baby bump on the red carpet at the premiere of Hardy's new movie, Legend - along with their pet pooch, Woody.)

In the film, Hardy plays both Ronnie and Reggie Kray, the infamous gangster twins who not only ruled London's East End through extortion, intimidation and robbery, but the entire capital by the mid-Sixties, where they hobnobbed with the rich and famous and exerted a hefty amount of control over the 'British Establishment'.

But things eventually started to derail. In 1966, Ronnie shot and killed a member of a rival gang in a Whitechapel pub, and the following year, Reggie, still grieving from the death of his wife Frances (played by Emily Browning in the film), killed a Kray associate in front of dozens of witnesses at a party. In 1968, after a long-standing investigation headed by Leonard 'Nipper' Read (Christopher Eccleston), they were arrested and sentenced to life in prison.

Legend's co-writer and director Brian Helgeland, who won an Oscar for the L.A. Confidential screenplay, has remarked: "They are at the heart of endless stories of both impossibly psychotic gangsters and, at the same time, 20th century Robin Hoods, politely holding the door open for Bethnal Green grannies."

Hardy insists there was no persuasion needed to play both twins. "Absolutely none. I wanted it. It was just a question of how I was going to get it."

There has been talk he was more interested in portraying Ronnie, the psychotic, openly gay brother who was eventually certified insane, and spent most of his life at Broadmoor Hospital before dying of a heart attack in 1995.

"If I had to choose between the two, then yeah, there was a moment in the conversation where Brian wanted me to play Reg, 'cause Reg was his lead. And me being me, well, it wouldn't be me if I didn't go for the other one immediately. But Ron is the firework in many ways."

Helgeland has revealed that Hardy in "Ron mode" was a lot easier to deal with than when he was on set as Reggie.

"I was a bit less confident in playing Reggie [who was released from prison on compassionate grounds six weeks before cancer claimed his life in 2000]," the actor admits. "I find straight leads really quite complicated, because they don't do anything. Things happen to them and they respond to the environment. It's quite 'plod, plod, plod' and kinda boring.

"It's very easy to play Ronnie because there's an unpredictability to him, so my brain can start to respond in a dramatic environment to that type of mechanism," he continues.

With the film's tight budget and schedule, cramming 100 locations into the seven-week shoot, Hardy would generally start the day as whichever brother had more screen time. This would often be Reggie, and when those scenes were done, he would disappear into make-up and wardrobe for an hour, adopt the wig, teeth, and plumped up the nose, and reappear as Ron.

"There was no CGI, we didn't have the budget for it, so it was back to old-school tricks, split screen and talking to a tennis ball or Jacob [Tomuri, Hardy's stunt double]. At the same time, you've got the rest of the cast who've got to deal with the fact we've got a split dynamic in the room, so it was kind of mathematical in a strange way."

In preparing for any performance, Hardy explains: "It's always a question of research and whether you've done your homework."

He talked to "various members of that world in private meetings", studied photos, and watched the small amount of footage of the Krays that exists. "But you can't really take a lot from that because they were on show, and you can't tell whether that's their true voice or mannerisms."

Now with the film in the can, he reflects on the experience with "a healthy indifference".

"It was a thesis I worked on for a little bit, and that's where I leave it, at the end of the day," says Hardy.

"I'm healthily indifferent to anything really, so I can invest in the next thing that comes along."

:: Legend is released on Wednesday, September 9