Starring in three of the most keenly anticipated film releases of the season – the stylish British crime thriller Welcome to the Punch, Danny Boyle's Trance, and Filth, based on Irvine Welsh's novel – he is also playing to a sold-out theatre every night in the critically lauded Macbeth. No wonder he is talking dreamily of a nice lie-down when he arrives at the Trafalgar Studios in London.
"I've got a wee foldy-outy bed. I'll get my sleeping bag and sleep there for a couple of hours."
But not before we've talked New York, Glasgow, bruises, drug-addicted cops, Danny Boyle, where to go for the best drama training, and tearing up the tarmac on Top Gear. Just as well he is talking faster than the car that is driving him across London.
First, Welcome to the Punch. Starring McAvoy, 33, as a London detective taking on a career criminal, Eran Creevy's thriller blends Hollywood cool and British grit with Hong Kong action frenzy to create a picture that packs a wallop.
McAvoy sees the film, produced by Ridley Scott, as taking Hollywood and Hong Kong on at their own game. "It's slick, in a lot of ways beautiful, and aspirational." And it allows him to hurl himself about like a sock in a tumble dryer. "I've always been quick to jump off something," he says of stunt work. "You don't have to convince me too hard to do a bunjee jump."
If anything, Creevy had to hold him back. "I know you hear on films, 'I did most of my own stunts,' but James really did. He's got that body, he's wiry, he can take a lot of hits."
He is certainly taking them in Macbeth. Jamie Lloyd's muscular production, complete with Scottish accents, has McAvoy's king stalking a dystopian, war-ravaged Scotland.
"You're having a mental and physical breakdown throughout the course of the show every night. It is one of those parts, those plays, where the audience is willing you to dash yourself on the rocks, both artistically and actually a little bit.
"It's all very controlled and we're trying to make sure nothing like that would ever happen of course, but we have to go so far to make people feel like anything could happen, make it seem like we are on the verge of losing control. That's not only a hard line to ride, it's also an exhausting one. But I'm loving it, absolutely loving it."
He first read the play as a third-year pupil at St Thomas Aquinas in Glasgow. In fact, it was Macbeth that started it all for the teenager from Drumchapel. His English teacher lived next door to David Hayman, who was appearing in Lady Macbeth at the Citizens at the time. Hayman gave a talk at the school, later cast McAvoy in The Near Room, and the wages from that helped to support him at the RSAMD in Glasgow. Everything else – Shameless, Band of Brothers, The Last King of Scotland, Becoming Jane, Atonement, Wanted, X-Men, The Conspirator – followed. Macbeth might have been dealt a bad hand by Wullie Shakespeare, but he did McAvoy a good turn.
McAvoy has helped himself, in turn, by playing a wide variety of parts ranging from Idi Amin's doctor in Last King to an assassin in Wanted. He didn't set out to be a character actor, but it has worked to his advantage. He is now so well known in the US that he can open a picture there. As a producer on Punch put it: "To get the movie to the budget we made it for, you need a James McAvoy."
The man himself says: "At the beginning of my career I just set out to hopefully dupe people into giving me any kind of work, and that was a lot of character work. I was just happy to get anything and I'm lucky that I've not been pigeon-holed too much. I've started to plan things a bit more now, but until the last three or four years I never really planned anything."
At the end of March he will be seen playing an auctioneer in Trance, alongside Vincent Cassel and Rosario Dawson. Boyle and Creevy are two of the most energetic directors he has ever worked for, he says, adding that he can see why the Olympics opening ceremony was such a success. "Not only was Danny Boyle a good director and came up with great ideas, but all those people were not just doing it for the Olympics, they were doing it for him."
As for Filth, out this summer, expect the unexpected, he says. "Some people will just hate it, but there is going to be a lot of people who wouldn't expect to like it who will find it entertaining, interesting and emotionally powerful." In a film delving into alcoholism, drug abuse and mental health, McAvoy plays Bruce Robertson, the Edinburgh cop you wouldn't want escorting your granny across the road. "It is not what you usually expect from me. It is not Trainspotting. It is very Irvine Welsh but it has got its own voice."
While in Scotland filming Filth he stayed in his new place in Glasgow. He thought he might find it strange, having been in London since 2000, but not so. "It made me think I could live here dead easily again." If not Glasgow or London then New York, where he spent last summer filming the two-part The Disappearance of Eleanor Rigby, with Jessica Chastain, a drama set inside a couple's marriage.
McAvoy has been married to fellow actor Anne-Marie Duff for seven years and they have a toddler son, Brendan. Though a dad now with a family car to match, he still rides motorbikes. Being able to listen to a bike engine and change gear at just the right time probably stood him in good stead for Top Gear's "star in a reasonably priced car" spot. "I'm probably more dangerous in a car than I am on a motorbike; on a bike I'm very mindful of the fact that if you make a mistake you're dead."
He won't be going on the road with Macbeth as he has to start shooting the new X-Men movie, Days of Future Past, soon. Whatever he does in future, he won't forget the years spent at the RSAMD, now renamed, much to his approval, the Royal Conservatoire of Scotland. When funding cuts and restructuring threatened in 2008, McAvoy jumped into the fray. It's the best training you can get, he says. The experience he gained – including 20 plays in three years – was invaluable, as was the way it opened the door to the world of acting and beyond.
"If you can't empathise and imagine what it is like to be somebody from somewhere else your world becomes very small and you can only do one thing. I went in there being able to do 'angry young Glaswegian' and that was about it really. I came out being able to do a lot of the stuff that I've done."
Welcome to the Punch opens in cinemas on March 15. Neverwhere starts March 16 on BBC Radio 4.