Playing a robot is no mean feat.

Imagine wearing a rigid suit that covers everything other than your eyes and nostrils, affecting your breathing and leaving you with very narrow vision and unable to hear very well.

Then there's the four-and-a-half hours spent in make-up every morning.

That was English-French actress Stacy Martin's experience on the set of new sci-fi thriller Archive, written and directed by Gavin Rothery - and she confides she "had moments where I was definitely quite moody".

But the costume was also helpful for the 30-year-old, whose breakthrough role was in 2013 film drama Nymphomaniac.

"Having this sort of armour, that was also quite restricting, was something that was actually really helpful for the character, because she struggles with her identity and who she is, and learning how to move in a different way - or learning how to breathe - was part of that character's journey, for me," she says.

Archive, which is set in the future (the year 2049) also stars Theo James - known for the Divergent film series and ITV drama Sanditon - as a roboticist named George Almore.

He has been working on a model that is a true, human equivalent android, and his latest prototype, J3 (Martin) - which has been achieved through two earlier prototypes, J1 and J2 - is almost complete.

What soon becomes clear is that George has secretly skewed the focus of his work: developing the robots towards the goal of creating a simulacra of Jules, his wife who died in a car crash (also played by Martin).

Jules is still present in George's life via a new form of life-extension technology - the Archive. But the Archive unit is under threat, and if George isn't to lose his wife completely, he urgently needs to complete the construction of J3.

The detail that Rothery has put into the world he has built within the film is seriously impressive; it really immerses you.

What also struck James, 36, about the script was that it was a "really interesting conceptual piece of work".

"It had something interesting to say about the quality of human life - you know, what it means to be human," muses the actor, who was born in High Wycombe.

"Beyond that, the idea of trying to recreate love - or a piece of someone's soul, however you want to define it - in something that was mechanical, essentially, and how far you can go to create that."

So, how did James try to understand his character's motives?

"You have to bring a piece of yourself to every character you play, so you try and see parallels in your own life and imagine how far you would go if you had lost the most important person to you, so you find some mutual ground there," he suggests.

"Also, I think I was drawn, personally, to the idea of the existential question of, 'If you imbue something with enough quality and characteristics of humanity, at what point does it become human?'"

Martin joined the cast quite late - by the time the team got in contact with her, it was just three weeks before quote shooting.

But she was drawn to the role because she "needed something a bit different" at the time - and she also liked "how much detail and how much love there was in the project".

"I don't know much about sci-fi and I was just very naive about that genre and, just by talking with Gavin, you really felt his passion for that genre but also for film-making and for this story that he was wanting to explore."

Rothery, who originally worked as an illustrator and comic artist, came up with the idea for Archive after he "had a really bad weekend".

"As a freelancer, both my computers died," recalls the film-maker, who also worked on sci-fi drama Moon. "It was a Sunday afternoon and I couldn't do anything to fix them. I lost a load of data - some kind of power surge, I never really found what happened.

"It cost me a couple of thousand pounds getting data recovered from hard drives, it was awful.

"I felt like my computers had killed themselves, basically, to spite me. It felt like a personal attack. So that kind of idea of a computer killing itself to spite somebody really lodged in my brain.

"That then led me into the story arc of what if there was somebody creating a human equivalent machine intelligence, and as soon as he turned it on, it just killed itself? So, it was kinda dark. But my head was in a dark place. I was in a bit of a funk - losing all my data was bad."

Discussing his cast, Rothery quips: "It's tricky when you first start meeting movie stars because everyone's really handsome and beautiful and smart and rich and you're just like, huge imposter syndrome. But you've just got to work your way through it."

He describes James as "super-smart, super-handsome, super-engaged, super-talented".

"I should really hate that guy, but I can't help but love him, he's awesome. He's just got so much going on.

"And Stacy - again she's just got so much going on. [She is] very sophisticated, she's French, she's very cool."

Both stars have new projects they hope to be working on in 2021; for Martin, it's Brady Corbet's feature film, The Brutalist.

"And then, really, I think it just depends on where that goes," she says. "It's hard to plan in a pandemic and I've sort of given up on having a plan, which is great!"

"I would echo Stacy's sentiment," follows James. "But, yeah, I'm hoping to do a remake of a French-language film. It's a small movie, but it's quite a special film."

Any James fans hoping to see more of him in Sanditon (and there were many - a petition on to see a second series made has attracted more than 80,000 signatures to date) might be disappointed.

Asked about the #SaveSanditon campaign, and whether he'd be open to doing more of the period drama - which was an adaptation of Jane Austen's famously unfinished story of the same name - he said: "It's really amazing that people responded to it in that way; I kind of always saw it as a single season though.

"I never saw it as more than that - I kind of liked the way it ended in a kind of slightly off-beat way that you wouldn't have necessarily expected from Jane Austen."

Well, at least there's Archive to watch instead...

Archive is released on prime video from Monday.