We're not sure we would recommend James McAvoy's 'bulk up quick' regime

Playing the lead role in a dark, hard-hitting movie about personality disorder sounds like a tough enough job for any professional actor – but playing nine?

In last year’s Split, X-Men star James McAvoy plays Kevin, a man whose dissociative identity disorder sees him identify with nine completely different personalities.

And with those characters raging between a nine-year-old boy, to an obsessive kidnapper, to a prim English lady named Patricia, it’s no surprise he had to keep himself in top form.

With only a relatively short amount of time to get in shape for the role, based on the true story of Billy Milligan, he told an interview with Mr Porter: “I Googled ‘good way to put on muscle quick’, just went into a gym and did it myself: a power-lifting routine called 5×5.

Floella Benjamin to get Bafta Fellowship for ‘tireless support of children’

King’s charity reveals next round of food waste workshops backed by Jamie Oliver

“You do five different exercises four or five times a week, and they’re huge, big exercises. Pick something up and do that.”But it wasn’t just the exercise. He also revealed how he forced himself to get through 5,000-6,000 calories per day, mainly in the form of pure meat.“Instead of eating two eggs in the morning, I’d eat eight … then a snack of chicken breast … then two chicken breasts for lunch, and then a steak for another snack … then two salmon steaks for dinner,” he said.Describing the intensive regime as super simple, he said he was “quite chuffed” with the results, which saw the 5ft 7 actor become “relatively bigger”.

On a more long-term basis, the Glaswegian also revealed that he had recently veered away from whisky as his tipple of choice. Not for the health benefits so much as because it apparently turns him “a wee bit fighty.”

Admitting that he is a “consumer” who will “tan the lot” of whatever he happens to have in the house, he told Mr Porter: “I still drink, and sometimes have a lot of drink … But I just don’t want to have alcohol in the house any more.”

But the big body transformation – not the first he has challenged himself with over his 22-year career – isn’t the only major change he went through last year.

Commenting on his split from wife of 10 years, Anne-Marie Duff, he revealed his life has “massively changed” but that things are all good.