ACTING is a game of hard knocks as Emun Elliott can attest to. Let’s rewind a few decades to when the Edinburgh-born star landed his first big role. Elliott was six and had been cast as the caterpillar in Alice in Wonderland in the school play.

“I wanted to do it because of the costume,” he recalls. “They had showed us pictures and the costume was incredible: he looked like a real caterpillar.

“I thought I was going to get this cool caterpillar suit and a little cane to walk with. Then the costume came out and it was just a duvet that had been spray-painted green. That was a bit of a let-down …”

Yet, as the old adage goes, the show must go on. “I did a song and dance number about keeping it cool,” continues Elliott. “I got to use the cane and had an American accent which must have been awful. But it was a lot of fun. That is probably when I caught the acting bug. I loved it.”

While it was a somewhat inauspicious debut, it didn’t put him off. Elliott has since gone on to win roles in Game of Thrones, Star Wars: the Force Awakens, Prometheus and the big-screen adaptation of Irvine Welsh’s Filth among others.

The 33-year-old actor will return to television screens on Tuesday alongside Broadchurch actor and new Doctor Who, Jodie Whittaker, in the BBC drama Trust Me.

Whittaker plays nurse Cath Hardacre who, after being sacked for whistle-blowing, seizes the chance to rebuild her life by assuming her best friend’s identity as an A&E doctor. She takes a job at an Edinburgh hospital posing as Dr Ally Sutton.

Elliott’s character, Dr Andy Brenner, is tasked with showing the enigmatic Cath/Ally the ropes. “I take her under my wing,” he says. “My character is sort of a foil to Jodie’s character. He knows exactly what he is doing: experienced, unflappable and always keeps his calm.”

Before filming began on the four-part psychological thriller, the cast – which also features Sharon Small and Inbetweeners actor Blake Harrison – were given what Elliott calls a “backstage tour” of St John’s Hospital in Livingston, West Lothian.

The show’s writer and creator, Dan Sefton, a doctor with two decades of experience working in the NHS, spent a couple of days getting the actors up to speed with the complex medical procedures that viewers will see on the show.

“Truthfulness and accuracy are important in any hospital drama because we need to look like we do this every day,” says Elliott. “Dan took us through procedures that were specific to our story and we would have to pretend to do on screen.

“We learned how to fix a collapsed lung, put in a chest drain, insert a syringe and clear airways. It was a world completely removed from the one I’m used to.

“Learning things where the stakes are so high – it is literally life and death that you are dealing with – felt very real. By the time we went on set, we were pretty confident about what we needed to do.”

Did Elliott find himself squeamish at all? “I thought I would be,” he admits. “But it is strange because when you have to do it yourself, there is no time for squeamishness.”

Could he utilise these skills if faced with a real-life medical emergency? “I hope so. Some of the basic things. It is quite easy to get ahead of yourself. If it came to doing these things for real I would panic.

“But there are definitely certain first aid techniques that I picked up. Hopefully I won’t have to use them but if need be I think I could be pretty handy.”

Not everything went quite to plan. “When Dan was taking us through how to insert a needle into a patient’s arm he actually insisted Jodie try it on him. That was very brave of him, but brave of her too, I think.

“Jodie managed to summon up the courage to do it and everything seemed to go perfectly until the needle went into his arm and then the blood started spurting out furiously.”

Whittaker, having executed the procedure almost seamlessly, had neglected one vital step. “She forgot to cap it. There was literally blood up the walls,” laughs Elliott. “Dan handled it well. It was lucky there was doctor in room, even one with a needle poking out of his arm.”

Elliott talks warmly about the close bond he forged with Whittaker. “It was loads of fun. We got on straight away,” he says. “I’ve been a huge fan of Jodie’s for a long time and that was a big reason why I was so keen on doing this one.”

When we speak it is before Whittaker’s casting as the new Doctor Who is announced. Catching up a few weeks later, Elliott insists he was as much in the dark as the rest of us. “I had no idea,” he says.

“As far as I’m aware, nobody was in the know. If you can trust anyone with a secret it is Jodie Whittaker. She must have been going out of her mind.”

Elliott is clearly tickled by the idea of Whittaker playing a doctor and then the Doctor.

“She is going to absolutely kill that role. It is not only the fact she has made history as the first female Doctor Who, but also because she deserves it more than anyone I know. She is a fantastic actor and a brilliant person. I’m over the moon for her.”

As his voice drifts down the line from Edinburgh – where Elliott is perusing the Beyond Caravaggio exhibition and has just been given a stern ticking off by a gallery attendant for talking too loudly on the phone – there is exciting news of his own to share.

He has been cast in a film based on Fiona Shaw’s novel Tell It to the Bees, a period romance due to begin shooting in Stirling this month. Anna Paquin, Holliday Grainger and Kate Dickie will also star, with Elliott playing Grainger’s husband.

The story chronicles a budding 1950s relationship between a single mother whose marriage has broken down and the town’s newly arrived GP.

“It is set in Scotland and so I get to do my own accent again – I might go slightly more west coast this time. We have got a fantastic cast. Kate Dickie is playing my sister. I’m a massive fan of Kate’s and I’ve been in a few things with her. We did Game of Thrones and Prometheus together.”

While work typically takes him all round the world, Elliott has spent much of the past 12 months on home soil. Prior to shooting Trust Me, he had roles in the BBC Three drama Clique and the Christmas special of Jonathan Creek, all shot in Scotland last year.

Elliott believes the growing number of productions being made here only serves to bolster the argument for a purpose-built film and TV studio.

“If that comes to fruition it would be a fantastic thing because it would mean more work,” he says. “Creative people in Scotland should be able to work in their own country. The more opportunities the better.”

While the interiors for Trust Me were shot mainly in Glasgow, Edinburgh provided a commanding backdrop for the unfolding action and Elliott is clearly relishing the chance to show off the city where he spent his formative years.

“They have captured Edinburgh in the most beautiful way,” he says. “We actually shot a scene on Portobello beach, which is where I grew up. My mum and dad still live there, as do my sister, brother-in-law and nephew. It all felt very close to home.”

Did he pop round for a cup of tea? “I did,” he says, smiling. “My mum made sure of it. It was lovely to be back.”

Elliott is the eldest of two children. His father Reza is a Heriot-Watt University lecturer and his mother Jacqueline a social worker. The actor was born Emun Mohammadi but plumped to use Elliott – his maternal grandmother’s maiden name – as his stage name.

“Part of me wishes I had changed it to something cooler with an X in it or a double V,” he muses. “Emun is tricky enough. The surname needs to be something simpler.”

Elliott attended George Heriot’s School in Edinburgh, describing himself as an all-rounder who enjoyed music, sport and drama. It was there that his love of acting blossomed.

“I was more shy than outgoing,” he says. “Part of the reason I liked getting on stage is because it gave me a chance to get out of my own skin. I was a sweet child and never got into a lot of trouble, although I could definitely be cheeky.

“I had a good time at school. I’m not sure I would have become an actor unless I had gone there because there was certain teachers, particularly my English teacher, who were encouraging. Through English I was introduced to drama and plays.”

He went on to hone his craft at the former Royal Scottish Academy of Music and Drama, now the Royal Conservatoire of Scotland in Glasgow.

“I have loads of fond memories and had an incredible time,” he says. “I didn’t really know what acting was until I went there. I hadn’t realised how far you could take it and how serious it could be. I had always thought of acting as entertainment until I went to RSAMD.”

The excruciating nerves of his third-year acting showcase remain palpable. “The pressure of that day and thinking: ‘The last three years have built up to the next three minutes on stage.’ I remember my phone ringing afterwards and it being the agent I’m still with today. The sense of relief …

“I feel for anyone having to go through that showcase because it doesn’t work out for everyone: there is either huge celebration or massive disappointment. It is a harsh welcome into the industry.”

Elliott won his first TV job in Monarch of the Glen alongside a young Martin Compston. “We have gone on to work together a couple of times, but our characters never seem to get on,” he jokes. “In real life, though, we get on really well – he is a lovely man.”

He was part of the original cast for the National Theatre of Scotland’s globally-acclaimed production of Gregory Burke’s Black Watch in 2006 before going on to roles in television dramas including Afterlife, Paradox, Lip Service, Vera and The Paradise.

Among his forthcoming projects is 6 Days, a thriller based on the 1980 Iranian Embassy Siege in London. Six gunmen took 26 hostages as they demanded the release of Arab prisoners in the Khuzestan Province of Iran, and their own safe passage out of the UK.

When Margaret Thatcher’s government refused to grant these demands, the gunmen murdered one of the hostages. Soldiers from the Special Air Service (SAS) were deployed to end the stand-off.

In 6 Days, Mark Strong plays a hostage negotiator with Abbie Cornish as reporter Kate Adie and Jamie Bell, alongside Elliott, as members of the SAS teams that stormed the embassy. It was filmed in New Zealand where the cast underwent a two-week boot camp led by former SAS soldiers.

Elliott was delighted to be able to use his own accent for the part. “Not because I don’t like doing other accents,” he clarifies. “But often I think Scottish actors are steered away from our own voices quite a lot. I have made it a determination of mine to avoid that.

“I will go up for parts set in ancient Rome or ancient Greece and be asked to do an RP English accent. I have always thought: ‘If these people are Greek or Roman and some of the cast are doing RP, then why can’t I be Scottish?’ I do seem to be getting away with it more as the years go on.”

One film he won’t be using his own accent for, however, is the Peter Greenaway-directed biopic, Walking to Paris. Elliott plays Romanian sculptor Constantin Brancusi who spent 18 months traversing Europe on foot to reach the French capital in the early 1900s.

“Not only did I have to learn a Romanian accent, I play violin, there is a lot of nudity and I do some crazy, mad things on camera,” says Elliott, referring to the comic, violent, sexual and romantic adventures that Brancusi experienced on his journey.

“I can’t give everything away but when that film comes out, you will see me doing things you have definitely never seen me do before.”

While Elliott alludes to there being a fair bit of nudity involved in Walking to Paris, he is sanguine when discussing the intricacies of stripping off for a role.

“You just get on with it, treat it as a job and do what has to be done,” he says. “There is nudity in all of Peter’s films, but the way he shoots things, every frame looks like a classical painting, which is part of the reason why I agreed to do it.

“He is one of the most interesting filmmakers alive. I wouldn’t have done it for anyone. You need to feel you are in safe hands and it is contributing towards a decent story before signing up to these things.”

The film is a work in progress. “We are almost there,” says Elliott. “It is just a case of getting that integral creative team in the same place at the same time. The film takes place over a year and a half, so it is a seasonal issue. We have shot winter and autumn, but need to shoot summer.”

Brancusi was a man driven by fierce artistic vision and the same could be said of Elliott, the actor notably reticent to be pigeonholed.

“In this career it is so hard to plan,” he says. “The important thing is to make the most out of the opportunities that you are given. Trying to forge a career and thinking: ‘I want to play this kind of character next’ or ‘I want to do that kind of story’, it just isn’t going to work.

“Life is similar. You have to always be prepared for what comes along. It could be anything and I love that element of surprise.”

Trust Me begins on BBC One, Tuesday, at 9pm