SCOTT Miller had never been on a horse in his life. His backside had never even sat on a Blackpool donkey. Not even a hobby horse.

For most people, it matters not a jot if they don’t know which way to face when on top of a mount. But that wasn’t the case with Miller.

At the end of last year, it was imperative the then 24 year-old could convince he was John Wayne, that he and six and a half feet of hair, teeth and muscle were one and the same.

The young man from Cumbernauld was going through a gruelling round of seven auditions for War Horse, the National Theatre stage show currently on tour.

“For one of the auditions I had to leap six and a half feet into the air and jump onto the life-sized horse,” he says of the giant puppet, his voice suggesting the fear he felt at the time. “Thankfully I managed to get away with it and look the part, even though I’d never been near a horse in my life.”

War Horse is an adaptation of Michael Morpurgo’s story of a young boy called Albert and his horse, Joey.

Set against the backdrop of World War 1, a deeply moving tale emerges when Joey, bought by Albert’s dad with the mortgage money in a fit of drunken bravado, is sold to the army as a war horse and sent to France.

However, Albert is determined he and Joey will be reunited and the play features Albert's attempts to connect.

War Horse, which premiered in London in 2007, is the most successful play ever produced by the National Theatre.

So no pressure to land the role, then Scott? “There certainly was,” he admits. Yet, while Morpugo declared that luck played a huge part in creating his story, the story of a war horse told to him by an old man one night in a Devon pub, Miller reveals fate played a big hand during another of his auditions.

The part calls for a young actor to replicate a perfect Devon accent; not one of the easiest to get to grips with, the danger being the performer sounds less like Ross Poldark and more like one of The Wurzels.

“As luck would have it, my flat mate when I was in drama school (at Lamda in London) was actually from Devon.

"When I heard the part called for a Devon accent my first thought was ‘I know how to do this!’ But what’s the chances of an actor student sharing a flat with a Devonian?

“It’s a very hard accent to grasp. It’s really nuanced. So I had to layer my technique with a 1914 sensibility. I spent a lot of time on YouTube as well, and doing work with a voice coach. But I knew the reward was huge.”

Scott Miller’s passion for acting is underlined when he reveals the unusual route to acting success. “I’d gone to Scottish Youth Theatre from the age of 11. I did a summer course and it really changed my life.”

Had his parents (his dad is a management consultant and his mother works for Police Scotland) had enough of their moping son and decided to get him out of the way for the summer? “Actually, that was the case,” he says, grinning. “Both of them were out at work full time and they had to find somewhere for me to go. But I loved SYT. I learned so much. And by the time I reached 14 I felt I knew what I wanted to do with my life. ”

He grins; “I knew by that time I wasn’t going to make it as a pro footballer.”

Miller didn’t do acting at school. “I wasn’t exactly embarrassed to act at school but I really wasn’t a huge fan of school. I didn’t fit in. I was disconnected and I only wanted to learn what I wanted to learn. Meanwhile, I got this idea into my head that my school pals were f*****s. I thought ‘Why am I hanging about with these people?’”

Miller was so sure he wanted to become an actor he left school aged 16, just after Fourth Year. “I needed to get out.”

He adds; “I suppose lots of young people feel disconnected. But maybe for me the feelings were accelerated because of the experience I’d had with SYT.”

Revealingly, he went back to SYT, this time to work on reception, “to do other jobs with the company, working up the ladder and learning.”

Did his parents have a say in their son leaving school so early? “I don’t think I was a loose cannon as such, but it was definitely about doing what I wanted to do. This was me at the time. Hopefully I’ve grown up a bit since then. But at least I was committed to being an actor.”

He smiles; “I wasn’t arrogant. Thankfully, my parents supported my decision.”

While working at SYT, Miller auditioned for a London theatre role, which he didn’t get, but the producer rated the keen young hopeful so much it led to interest from Vox Motus theatre company - who offered Miller a role in a new production, Dragon. Miller excelled as the tormented teenager who loses his mother in this story of isolation and adolescence. And he went on to feature in Glasgow’s Oran Mor Play, Pie and a Pint season.

At this point he was accepted for drama college (Lamda) and took off to London. But why not go in the first place? “I just never felt ready,” he admits. “I needed to grow up and SYT allowed me the place to mature. And at what age should you go to drama college? Can you go and learn to become other people if you don’t yet know yourself?”

His time was now. “I was trepidatious about moving to London,” he admits. “And when the buzz of arrival wears off you realised you’re in amongst lots of young actors who are really committed and so hard working. It’s a hard business to be in. Straight out of drama school I was straight into working in a bar. But that’s good. You meet lots of fascinating people, and you get a chance to learn about real life.”

How does he cope with auditions and rejection? “It can be demanding, but you have to accept that if the job’s not for you, that’s it. But I do try and be off-book before I go in, (having learned the lines). For this job, I learned two scenes. But by the last audition I knew all my lines. I like to be prepared.”

When Miller speaks of acting there’s a real sense he’s living the dream. He’s in his world, he’s soaking up every experience he can gain to make him a better actor. Even his personal life overlaps wonderfully. His partner, with whom he shares a flat in Clapham, is Scottish actor Joanne McGuinness, who starred in theatre hit Our Ladies of Perpetual Succour. “We met in Dragon all those years ago when she played my sister,” he recalls, grinning.

What’s it like having two actors in the one house? “It’s great. We help each other with audition scripts. She’s working a lot at the moment but I’d love the chance to work with her at some point.”

Miller’s commitment is paying off. As well as landing the starring role in War Horse, the actor appeared in his first film this year, Balance Not Symmetry alongside Laura Harrier of Spider Man and Black Klansman fame. “I play the guy who introduces her to world in Glasgow she’s never seen before. It’s a nice part.”

Miller savours, but also appreciates current success. And he no longer disconnects from old school friends. His leitmotif, you sense, is humility. “ I know for a fact I will have to go back to working in a bar one day,” he offers. “I’ll always be an actor, but not always a working actor. “

War Horse, the Clyde Auditorium, January 15 - February 2.