Really, Jack Lowden is explaining, if you wanted to, you could trace all of it – playing Morrissey in the days before he came out as an EDL sympathiser, appearing as the pilot who wasn’t Tom Hardy in the Second World War blockbuster Dunkirk, being arguably the hottest Scottish actor in the world right now – back to Riverdance.

No, honestly. “When my younger brother and I were something like eight or nine years old our parents took us to see Michael Flatley in Manchester,” Lowden is telling me. “I think the pair of us came out of that and went ‘We’ve got to learn Irish dancing.’

“Mum and dad found a place in Edinburgh and Calum and I were the only two boys in the class because we wanted to learn to tap dance like Michael Flatley.

“And from there Calum went into ballet and he is now a professional ballet dancer in the Royal Swedish Ballet in Stockholm. I gradually got encouraged away from the dancing. I ended up narrating all these shows in front of an audience and I absolutely loved it.”

So, there you have it. Riverdance is not only a prime example of Irish soft power and employer of numerous dancers over the years, it can also claim to be the starting point for Lowden’s current brilliant career, a career that has seen him go from ballet to blockbusters, via an Irn Bru ad, studying at the Royal Conservatoire in Glasgow, the inevitable role in the NTS drama Black Watch, winning an Olivier award for his take on Ibsen’s Ghosts in only his third theatrical job. One that will soon see him playing Lord Darnley in the upcoming Mary Queen of Scots film opposite Saoirse Ronan and Margot Robbie.

Born in 1990 (I know, I know, it’s sickening, isn’t it?), right now Jack Lowden is most definitely on the up. "I definitely feel it’s going up,” he admits, “which is quite cool. It’s exciting.

“I can’t choose entirely what I do yet, but I’ve been able to have a bit more choice and I certainly feel like I’m climbing.

“But, at the same time, I’m genuinely trying to pick things that are really challenging. I want to push myself.”

That’s why he’s going to do his first Shakespeare play (Measure for Measure) on the London stage this year. It also in part explains his latest project, Calibre, which had its world premiere at the Edinburgh International Film Festival last week and debuts on Netflix on Friday.

Set in the Highlands, it’s a thriller that sets a couple of urban types loose in the rural backwoods on a hunting trip that goes badly pear-shaped.

It’s a movie of low dread, impressive backdrops (“It’s hard to make Scotland not look amazing,” as Lowden points out) and a genuine shock moment, which, the actor admits, was one of the main reasons he wanted to be involved in the first place.

You could, if you were so inclined, parse Jack Lowden’s most recent big screen roles as essays in masculinity. From stiff-upper-lip heroism in Dunkirk to Beta male insularity in the Morrissey movie England is Mine. Now, in Calibre, he gives us what you might argue is a portrait of male weakness and the terrible things that it can make you do.

“As I’ve gotten a bit older I realised the most interesting parts to play are the ones that have a bit of self-doubt about them," Lowden says. "I really enjoy exploring that. Something like Dunkirk is very heroic. I did try to stick in a bit of self-doubt as well.

“When I meet people in real life … As soon as you see somebody’s weak spot I find it really endearing and I relax a lot more. And I kind of feel that with the characters. I do like characters who have some kind of crack in them, characters who you shouldn’t be afraid to dislike, maybe hate.”

Which rather begs a question, doesn’t it? Jack, what do you doubt most about yourself in the real world?

“I tend not to have moments of self-doubt in my personal life, but when it comes to work I care about it almost too much. I don’t walk off the set at the end of the day thinking: ‘I absolutely nailed that.’”

Hmm, doesn’t the fact that you're in such demand mean that you can start thinking you can't be too bad at this acting game? “You’d think it would …”

That said, he adds, he feels more comfortable on stage than he does in real life. “I don’t know why that is. I’ve never been nervous on stage. I just feel at home.”

“At high school I realised it’s what I can do,” he says. “It’s almost laziness in a way,” he says with a very Scottish sense of self-deprecation.

How does his Scottishness most manifest itself? “In really undercutting and underselling myself. As we all do.”

Clearly, the underselling isn’t working. As well as Calibre and Mary Queen of Scots, Lowden will soon turn up as a wrestler in Stephen Marchant’s Wrestling with My Family alongside Dwayne Johnson and Tom Hardy’s new take on the Al Capone story, Fonzo.

And when we speak Lowden is filming in the Dominican Republic on a new BBC slavery drama The Long Song. He’s not filming today, so, in between talking to me and watching World Cup football, he says he’s probably going to spend it in the sea, eating fruit and avoiding falling coconuts.

It must feel a world away from growing up in Oxton in the Borders. His dad worked in the Bank of Scotland for 40 years. His mum ran an art gallery, although Lowden says, neither were particularly artsy. They were, though, supportive in everything Lowden and his brother wanted to do.

“Me and my brother were obsessed with the ice hockey movie The Mighty Ducks," he recalls, "and I remember we got an ice hockey trial in Murrayfield and we couldn’t skate for s****.

“I’d say everything me and my brother have done was completely down to them. They never said no. If they needed more money they found a way. They never said: ‘It couldn’t be done.’”

After years in London Lowden is thinking of coming home now. “I’m looking to buy in Edinburgh,” he says. “There are a lot of Scottish actors and we’ve all been talking recently about that thing of having to move to London.

“It seems to be an exciting time to be trying to do it in Scotland. I’ve been lucky enough to do three films that have all been shot in Scotland,” he points out [along with Calibre and Mary Queen of Scots he filmed the golfing drama Tommy’s Honour here], “and I just don’t see why it can’t be done up there. I just think it’s a very exciting place to be at the minute and there are a lot of Scottish actors who are thinking twice about the whole London thing. ‘Do we have to do that?’

A studio might help of course, I suggest. “Oh, for Christ’s sake, will they not just do that?

“There’s phenomenal young talent kicking around now and the time is right to start making films in Scotland.”

Calibre streams on Netflix from Friday. A captioned screening of the film will take place in Filmhouse 2 in Edinburgh on Saturday as part of the Edinburgh International Film Festival