Charlie Hunnam doesn’t like hype, isn’t too fond of Hollywood, and isn’t one to brag. He is also very up-front about the fact that director Guy Ritchie initially showed zero interest in casting a rugged and beardy blonde as the eponymous monarch in the upcoming King Arthur: Legend of the Sword. And when asked how he came to land what is arguably his biggest role to date, he simply shrugs: “Fuck knows, because he didn’t want to see me. He wanted nothing to do with me!”

But the 36-year-old, who in his own words is “a likeable guy”, set to winning over the Snatch filmmaker on a visit to his London home. “I got to his house, sat down with the man, and we just talked and talked. After 90 minutes, I realised we had been talking exclusively about the California medical marijuana initiative,” says a bemused Hunnam, in a style rather reminiscent of a Guy Ritchie voiceover. “I thought ‘go with it, he’s still talking with me’. We went on for another hour or so, and when I left I thought, ‘Shit – we never said a thing about Arthur!’” Ritchie, however, instinctively knew he had the right man for the job and called the affable actor the next day to offer him the lead role.

The film promises to be a raucous re-imagining of the fabled classic, and rather than the traditional Camelot culture of valour, Hunnam is playing Guy Ritchie’s Arthur – a cheeky everyman, raised in the slums, unaware of his royal lineage until he drags the legendary sword from a stone. “It’s no accident that the studio picked Guy as the man to realise this vision,” says Hunnam. “This is one of the oldest stories, so for him to take it and create this fresh, brittle outlook in his very signature way – very punchy, gritty, cheeky – just excited me from the first time I heard he was doing it.”

With a stellar supporting cast including Djimon Hounsou, Eric Bana and Àstrid Bergès-Frisbey, along with Jude Law as the disgruntled and tyrannical crown-stealer set on foiling Arthur’s claim to the throne, and Peaky Blinders star Annabelle Wallis, it looks like Ritchie could have a hit to rival his equally outlandish interpretation of Sherlock Holmes.

David Beckham also makes an appearance as a knight – his second role in a Ritchie flick following a brief cameo in The Man From UNCLE – and while Hunnam says he personally wasn’t star-struck, having “never been a football man”, others on set weren’t so impervious to the ex-England captain’s charms. “The film crew in particular, the gaffers, the electricians… all those boys, they’re these butch, manly men, but they all turned into 15-year-old girls at a Justin Bieber concert because Beckham was on set,” Hunnam jokes. “I was like – pull yourselves together!”

I was just trying to keep up with all these burly, beefy guys around – they were everywhere

Despite the chaos he caused, Hunnam is only complimentary about the footballing legend himself, admitting it was easy to see how he became such a celebrated sportsman. “There was a work ethic and determination, because he wasn’t just there to have a laugh – he was determined and serious about doing a good job,” he explains. “He’d been working with an acting coach, which speaks volumes about his work ethic and shows that nothing happens without hard work.” The big question, though, is would he consider himself to be buddies with Becks now? “I’d be quite friendly with him,” he says with a cheeky grin. “He’s not on speed dial, but I’d definitely have a drink with him. He’s a great guy.”

For Hunnam, who has spent much of the last decade filming the dark and deeply serious crime series Sons of Anarchy, knighting up was a thrilling change of pace. “This was honestly one of the very best experiences – just for pure fun and adventure and really letting go – that I’ve ever had on a film set,” says the enthusiastic Geordie. “Guy would say to me, ‘Before we do this, the one thing I really want from you is to show up every day and have fun because if we’re having fun, the tone is where we want it to be and the audience are having fun, too.’”

Those unfamiliar with Sons of Anarchy – the hugely popular, edgy and violent American series following the lives of a close-knit outlaw motorcycle gang in California – may instead remember Hunnam from his breakout role in 1990s gay drama Queer as Folk. Shot when Hunnam was a skinny and disarming 18-year-old, he won over male and female fans alike with his pretty-boy features and cocky teenage swagger. Several high-profile film roles followed like Cold Mountain and Children of Men, but it was his turn as a football hooligan in Lexi Alexander’s Green Street that garnered him the most attention. Unfortunately, though, it was for the wrong reasons as film and footie fans alike mocked his dubious cockney accent.

He hit headlines once more in 2013 when he was cast and then withdrew (no pun intended…) from playing Christian in Fifty Shades of Grey, owing to conflicting film schedules with Guillermo Del Toro’s Crimson Peak. Hunnam has since said that it was “the worst professional experience” of his life, but that he simply couldn’t make it work. When asked how he now feels about missing out on such a lucrative role, the handsome star shrugs and says, “I have no regrets, really I don’t. This will sound so high-falutin and wanky, but I really do try to force myself to live in the present and not to project happiness on past or future events.”

Compared to his peers, Hunnam is a bit of an anomaly. Like his King Arthur alter ego, he has a sense of honour that is unexpected – and at times rather unhelpful when pursuing such a cutthroat career path. For example, his decision to shoot Crimson Peak over Fifty Shades despite Del Toro having months to recast and it being a much smaller role. Hunnam’s reasoning? Because he had given the cult Mexican filmmaker “his word”. He also pretty much shuns the Los Angeles party circuit, living on a ranch outside of Hollywood with his partner of 11 years – Morgana McNelis – and crumples and blushes at the slightest mention of any flattery.

But perhaps it is these perceived flaws that ingratiate Hunnam to the likes of Guy Ritchie, a man who also lurks on the edges of ‘the scene’ and directs his films like a maniac with a can opener, lifting the lid on conventions and delving deep to find what’s behind the narrative – an ethos Hunnam appears to share. “Arthur is a very big, glossy, commercial film, but at the heart of it, Guy and I were really trying to explore some interesting things about the human condition,” muses Hunnam. “About what it requires to overcome fears and trust our sense of hope. That’s what the story of Arthur is, overcoming those personal hurdles, in order to rise to the challenge of conquering the insurmountable odds of becoming the king of England and fighting in this incarnation, in a literal sense, the demon at the castle walls.”

Sword fighting requires immense preparation; it's definitely not as fun as it looks as a kid

Both metaphorically and physically Hunnam is a monster presence on screen, having bulked up from his naturally slender frame to become appropriately foreboding and ripped. “I was just trying to keep up with all these burly, beefy guys around me. They were literally everywhere. I couldn’t let the side down – I was King-fucking-Arthur! So I turned it up, got up to about 180 and that is not easy to carry around!” he says with a smirk, before adding, “I’m nothing like a lot of my characters, particularly ones I’ve played recently. Physically, I’m so far removed and I feel comfortable being slimmer. Not this freakish, abbed-out gym dude!”

Hunnam may have found fame as a teenager, but his obsession with acting came long before that, after watching adventure films as a boy – particularly John Boorman’s Excalibur. And while the actor seized his chance to fight, lead an army into battle and ride a horse with abandon on screen, there were aspects of the process that were less enthralling in reality. “Sword fighting requires immense preparation which is very labour-intensive; it’s not as fun as it looks as a kid,” he says, shaking his head. “It’s also a lot more mental than it is physical, oddly. The final scene is maybe seven minutes long, but you need to learn 700 or 800 beats, and know how that goes in succession in the dance. I found myself quite obsessed with running those sequences over and over.”

What is evident is that Hunnam has the swagger, charm and most importantly balls to claim his rightful place in Hollywood, but the question is whether he wants to. Unlike his regal alter-ego, Hunnam is in full control of his own destiny. “I’m in the best position I’ve ever been in career-wise, in terms of the opportunities that are being given to me,” he says. “But I feel more neurotic now than I ever have, because of all these fucking decisions I have to make all the time. There are now stakes to what decisions I make, but fuck that – there shouldn’t be. I can’t handle that in my life!”

King Arthur: Legend of the Sword is out on 19 May. Watch the trailer below: