Outlander star Richard Rankin on global fame as Roger Wakefield and his Glasgow childhood

First, though, there's his role in Outlander to chat about. Richard plays Roger Wakefield, an Oxford professor and the adopted son of an Inverness minister, who finds himself unwittingly embroiled in a time-travelling adventure.

Based on the bestselling books of Diana Gabaldon, the TV show has garnered millions of fans and made its cast into household names around the world. The third series, shot largely around Scotland, will air on Amazon Prime Video from next Monday.

Richard joined the cast in late 2015 after almost 18 months of feverish speculation. Other names in the frame to play Roger reportedly included Downton Abbey's Matthew Goode and former Game of Thrones stars Gethin Anthony and Richard Madden.

"Casting was thorough to say the least," says Richard. "It is the most thorough casting I have done on anything. They had me in time and again with different material and ideas for the character. They were very clear about what they wanted."

From the outset Richard, 34, was a firm favourite among many Outlander aficionados who lobbied passionately for him to get the role.

"Even from before I was cast I was one of their choices as Roger for a long time," he says. "That was bizarre and put me in a very strange position where I thought: 'I hope the execs on this show don't think I have started my own campaign to be cast …'"

The second eldest of four sons, Richard grew up in Glasgow. His father Colin, now retired, was a police officer while his mother Margaret continues to work in the hotel industry.

Richard spent his early childhood in the west end, where the family had a flat on Byres Road, before moving to King's Park on the south side (not Rutherglen as Wikipedia states) when he was 10.

His parents had their work cut out. "It was chaos with four boys in the house," he says. "I was always running away when I was younger. I was brought home by my dad's colleagues a couple of times for running off on mad adventures."

As we probe deeper into his past, there are moments where it feels like I'm playing amateur psychologist. Why did he run away? Was it about attention? Did he do it because he was bored?

"I think I was just adventurous," he shrugs. "Whenever there was any scaffolding up you could often find me at the top of it – or on tenement roofs. I would climb anything."

He has loads of stories in this vein, although Richard is adamant that there was no malevolent or troubling underlying reason for his high jinks. "It wasn't because family life was bad or anything," he asserts. "I was a handful. I was utter mischief when I was younger."

While Richard wouldn't begin acting until his twenties, there were signs of a budding performer long before that. "My earliest memory of music was listening to Billy Joel. I have many vivid memories of me dancing around in a nappy singing Uptown Girl."

As a youngster Richard went through a phase of pretending to be RoboCop, while other gems included doing a Michael Jackson impersonation concert in the school playground.

"I had bought smoke bombs," he says. "I'm not quite sure how I thought logistically I was going to have all these pyrotechnics going off. But obviously in a young boy's head there is lights, smoke and a full concert atmosphere.

"I managed to sell three tickets. It turned out an utter disaster and I split my head open trying to do a backflip off a pillar as my finale. The smoke bombs didn't work either."

Throughout his teens Richard continued to daydream about stardom. He began a course in IT at Glasgow Caledonian University, but a chance conversation while on holiday to Los Angeles would change his life path.

"I met a producer – I think he worked on The OC, although I'm not 100 per cent sure – but he was one of the execs on a show like that," says Richard. "He was at the Roosevelt Hotel on Hollywood Boulevard with his cast and they were chilling out."

The pair got chatting and the producer told Richard he had a good look for an actor and asked if he had ever considered it as a career? "I was like: 'OK, whatever …' but it was enough to plant the seed."

After returning to Glasgow, Richard auditioned for a place to study acting at Langside College. His early roles included BBC sitcom Legit and meeting a grisly end on Taggart – a rite of passage for any aspiring Scottish actor – before he joined the cast of cult comedy sketch show Burnistoun in 2009.

Parts in BBC war drama The Crimson Field and as a lottery winner in Kay Mellor's The Syndicate followed. Richard starred opposite Anne-Marie Duff in psychological crime thriller From Darkness, and more recently alongside Morven Christie and Vicky McClure in The Replacement.

Like fellow Scot Sam Heughan, who plays Jamie Fraser in Outlander, Richard has found himself in the odd juxtaposition where his fame has exploded internationally yet in his homeland he remains better known for other TV roles.

That may be about to change. It has long been a gripe that Scottish viewers have been unable to see Outlander on terrestrial telly, but in June it was announced that More4 had bought the rights to screen the first series from Sony Pictures Television.

Indeed, we should get to know his on-screen alter ego pretty well. "If we are talking about the books, I happen to know that Roger is very much still there in book nine," he says, referring to the latest Outlander novel that Gabaldon is writing.

"Diana does this thing where she releases little snippets, so there have been scenes that Roger has been involved in. Should we run in tandem with the books, I will be there in season nine."

Outlander series three is available on Amazon Prime Video from September 11. With thanks to the Soho Hotel in London (firmdalehotels.com) and Paul Smith (paulsmith.com)​