AS a wrestler-turned-leading-action man, Dwayne Johnson is no stranger to keeping his body in peak condition, so his preparation to play Hercules is a little unexpected.
"To prep as a demigod, in my opinion, it's the occasional glass of tequila," says Johnson. "Sipped, not a shooter, we're not back in college," he adds, grinning.
The 42-year-old, a 6ft 5in hulk in grey suit trousers, patterned shirt and waistcoat, had his heart set on playing the man born with the strength of a god when he first arrived in Hollywood.
That was a little over a decade ago, and while he'd already amassed a legion of fans as pro wrestler The Rock, he didn't, as he puts it, "have the juice or power to make it happen back then, but I kind of have it today".
That's thanks to fantasy movies like The Scorpion King (a film created just for him after his brief appearance in The Mummy Returns), comedies including The Other Guys and action dramas such as Pain & Gain, along with the hugely successful Fast & Furious franchise.
"I'm drawn to roles where the central character will have something to overcome, may fall down, but will get better in big ways by the end of the movie and then galvanise everyone else around him to get better," says Johnson, who makes for charming company, even if his answers veer towards the cliched, something he acknowledges himself at one point.
"I hope people watching Hercules will walk away incredibly entertained, but I also hope they walk away (and it sounds a little cheesy) with a sense of power," he explains.
Dwayne as Hercules
"One of the reasons I wanted to take this role is because there's such great value, not only in this character, but also me and you relating to it, that when we embrace the person we were born to be, we become so super-powerful."
Cheesy it might be, but Johnson has become something of power player, solidifying himself as a global box office success with film revenues grossing in excess of 1.5 billion US Dollars worldwide - Forbes ranked him as the top-grossing actor in 2013.
The father-of-one (he has a 12-year-old daughter with ex-wife Dany Garcia) wasn't destined for the movies though. Born in San Francisco, he lived briefly in New Zealand before moving to Hawaii, where he excelled at sports.
In 1996, after graduating from the University of Miami, he decided to follow in the footsteps of dad and grandfather and join the world of the WWE. Within seven years, he'd became one of the industry's most charismatic characters.
Given the showmanship required in wrestling, the big screen wasn't such a huge leap, but Hercules is the role he's been waiting for.
This version, inspired by Steve Moore's comic book series Hercules: The Thracian Wars and directed by Brett Ratner, of the Rush Hour movies and X-Men: The Last Stand, sees Hercules as a man struggling to live up to his own legend.
"When we meet him, he's in exile suffering with regrets, fighting only for gold," says Johnson. Only when a warlord threatens peace is he forced to stand up and embrace who he really is.
As soon as the project was green-lit, Johnson decided "the best thing I could do was really get to know the graphic novel, get to know the script and spend a lot of time with the director".
He also re-watched the classic 1958 movie and its sequel Hercules Unchained, starring bodybuilder-turned-actor Steve Reeves in the title role.
"I used to have one of those old posters of Reeves that looked painted when I was growing up," Johnson reveals. "There's that iconic moment when Hercules breaks the chains from the pillars and screams, 'I am Hercules'. For me, as a kid, that was mesmerising."
The team decided to retain such iconic moments in this new retelling - "There are only so many ways you can shoot that," Johnson notes, "so we approached it as, rather than make it different, embrace the power of what it is".
Although no stranger to physically punishing himself for roles, he makes no secret of the fact that this one has been the most demanding of his career. "I started prepping about six months before shooting began, because it's Hercules," he explains. "And when Brett and I first met about the project a couple of years ago, we agreed you get one crack at it."
But the challenge wasn't so much attaining a Herculean physique (he added 35lbs of muscle), but maintaining it. "We shot for about five or six months in Budapest, and so everything's got to match from day one to day 95."
The cast and crew would often spot the action star hitting the gym - twice - before getting to set, and Ratner's joked that Johnson walked up to him during the shoot and said: "Don't screw this up Brett, I'm working so hard!"
The Hercules cast at London's Trafalgar Square
He might have eased off the Herculean work-outs but, as an action man, it's not like Johnson can let himself go. He's already begun work on the disaster movie San Andreas and recently wrapped on the seventh instalment of the Fast & Furious series. The movie was forced to halt for a while, following the tragic death of fellow actor Paul Walker in a car crash last year.
"Any time you lose a loved one, it's tough, and we all deal with it in our own certain way," says Johnson. "I think the studio was very challenged to try and work out how we were going to make that movie without Paul.
"It's going to be very special," he adds. "It's going to be emotional and I think audiences are going to appreciate it."
EXTRA TIME - FROM SPORTS TO SCREEN
Arnold Schwarzenegger - Long before The Terminator hit screens in 1984, Arnie had a successful career in bodybuilding, winning Mr Universe for three consecutive years.
Vinnie Jones - The former Chelsea midfielder was once known for his aggressive style on the football pitch but is now a famous big screen hard man, after making his film debut in Guy Ritchie's Lock, Stock & Two Smoking Barrels in 1998.
Jason Lee - He may be best known for playing the title role in hit TV series My Name Is Earl, but Lee was a prominent professional skateboarder before transitioning into acting.
Eric Cantona - The Frenchman was initially a star at Old Trafford before becoming a screen star. He turned to acting after retiring from professional football in 1997.
Jason Statham - Action star Statham was on the British national diving team, finishing 12th in the 1992 World Championships, before plunging into a movie career.
Hercules is released on Friday, July 25.