You might be more familiar with his super trim form in Magic Mike and The Dallas Buyers Club, but Matthew McConaughey said he had a great time chomping cheeseburgers and chugging bear to bulk up for Gold.

In a career first for the Oscar-winning star, he packed on 47 lbs in pure chub to play gold prospector Kenny Wells.

It may not have done wonders for his health, but he said his indulgent diet turned him into Captain Fun for his three kids.

He told E! News: “I was Captain Fun because I was (saying) yes to everything…I was a really fun dad for that six months because I was like, ‘No, pizza night’s not just Friday night, it’s Tuesday night, it’s Wednesday morning.’

“My favourite food is cheeseburgers, so I was eating cheeseburgers all the time – not that much sweets, cheeseburgers and beer will do the trick.”

Any attempts at exercise were also strictly off the schedule, and he even admitted to taking the lift rather than a flight of stairs at every opportunity.

Coming to screens later this month, the Stephen Gaghan film sees Matthew, 47, play a failing businessman embark on a hair-brained scheme to dig for gold in Indonesia.

As well as putting on the hefty amount of weight – almost 10 lbs more than what he shed for his Dallas Buyers Club role – he covered his shaved head with a toupee and his teeth with custom-made veneers.

Typically an athletic chap, it’s no surprise that he couldn’t wait to shake off the look as soon as filming wrapped – just in time for the red carpets.

But it wasn’t easy.

Describing the dramatic lifestyle shift as “daunting,” he said the toughest part was crossing back over the 210 lb mark, but it was plain sailing back to his old self after that.