Gold: Matthew McConaughey hits the big time with his new film

When Matthew McConaughey dropped over three stone for his show-stopping portrayal of AIDS sufferer Ron Woodroof in 2013’s Dallas Buyers Club, it was a make-under that drew gasps.

The one-time romcom king, cast for his chiselled pretty boy looks, had ditched the tried-and-tested heart-throb tag in favour of serious drama. A move - brilliantly dubbed ‘the McConaissance’ - that subsequently earned him his first Oscar.

Three years on, and McConaughey’s attracted critical acclaim for his role opposite Woody Harrelson in HBO series True Detective, and impressed in Christopher Nolan’s sci-fi blockbuster Interstellar, securing his spot among Hollywood’s greatest.

His latest incarnation is Kenny Wells: a balding, overweight goldmine prospector at the heart of Stephen Gaghan’s latest big-screen epic, Gold.

Inspired by actual events, the crime-adventure, set in Southeast Asia, follows the ambitious tale of one man’s American dream, and everything he’ll do to keep it from falling apart.

Intrigued by the concept of how far one man would go, it’s a role McConaughey couldn’t turn down.

“Kenny had a literal dream that he knew somebody that knew where the gold was, and he takes a one-way ticket to Indonesia to chase that dream down and make it so,” says the 47-year-old actor, who’s also currently lending his voice to musical animation, Sing.

“I don’t have - that I can think of - such specific dreams. I try to go about my life every day to keep me in the dream, maybe,” he adds, smiling.

“But Kenny has nine lives... I don’t think I have cheated death as many times as he has.”

Dressed in blue jeans and a dark denim shirt, a heavily bearded McConaughey - sat almost at a slump, legs crossed casually at the knee - is in good spirits. Calm, collected and only too happy to chat.

Afterwards, he’ll be leaving the hotel room to “tune in” to Trump’s inauguration, but makes it clear he’s not here to talk politics. In fact, any questions outside the remit of the film are politely steered back, but he talks with a sincerity and charm that make him instantly likeable (even if his constant eye contact feels slightly intense).

As Wells, McConaughey is unrecognisable, the physical transformation this time helped by a customised balding toupee, prosthetic crooked teeth and a 40lb weight gain, thanks to a diet of beer, cheeseburgers and milkshakes.

It was a regime that earned him the title of ‘Captain Fun’ at home (he lives in his native Texas with his Brazilian model wife, Camila Alves, and their three children - sons Levi and Livingston, and daughter Vida).

“For six months, I had a rule that everyone had to say yes to every desire they wanted, 24/7,” he recently revealed during an appearance on The Graham Norton Show. “I was a real yes man; pizza night could be any night, and if the kids wanted to go bowling at midnight on a school night, that was great. Cheeseburger and beer for breakfast was a great idea too. I really relaxed on the rules... It was fun and my family kind of misses me being a fat ass.”

While you certainly can’t tell today that McConaughey was ever out of shape, I wonder if his extreme dieting ever gives him cause for concern long-term?

“I take pretty good care of myself, and even in putting on all the weight or losing all the weight, I am listening - or I do my best - to listen to my body along the way,” he reasons. “I think the body is more resilient than a lot of people give it credit for. If anything, I think I looked at it as a possible health benefit to just stretch, so to speak...”

He says he loves to “play real people”.

“That’s part of what is wonderful about my job; doing my best to go and inhabit somebody else. Yes, it is the actor doing it, it’s coming through my vessel, but that’s part of the fun, that’s part of the adventure.

“Our job is to expose humanity,” he continues. “So I can go into a guy and love inhabiting him and feel like I know him so well and he is a real person. That’s the fun of what actors get to do.”

He admits his Academy Award win boosted his faith in his ability to tackle more complex roles.

“It gave me more confidence in the choices I was making, to keep them very personal for me. To make sure I was still choosing roles that scare me, that I’m not sure how I’m going to pull off but I am going to dive in and give it a punt.

“Besides that,” McConaughey adds with a smile, “another outcome of something [that] has changed since winning, is chefs give me a couple extra shavings of truffle on my pasta now, without me asking...

“That’s a nice perk!”

:: Gold is out in cinemas from Friday, February 3