Having cut his cinematic teeth on bleak 2011 crime drama Snowtown and 2015's stylised, atmospheric Shakespeare adaptation Macbeth, Justin Kurzel has established himself as one of today's most intriguing directors – a reputation he upholds as we edge closer to the release of Assassin’s Creed.

Starring the likes of Michael Fassbender, Marion Cotillard, Michael Kenneth Williams, Jeremy Irons and Brendan Gleeson, this videogame adaptation is already looking like one of the year's most exciting releases. We spoke to Kurzel about working with Fassbender (who also produces) and bringing the computer world to life...

Q: Can you tell us a bit about how you got involved with Assassin's Creed?
A: When Martin first started talking to me about the idea, I wasn't aware of Assassin's Creed, so he started talking to me about a concept; an idea of the film that had to do with, "Wouldn't it be amazing if you could have access to the memories of your ancestors, and actually see them, understand and somehow that those experiences of the past would sort of define who you are?"

I thought that that was a really interesting idea that, "Wow, why can I suddenly sort of pick up a violin and play it beautifully?" Where does that come from, the idea that your ancestor had learnt it and had become brilliant at it, and that is somehow passed on in your DNA to you and you instinctively are able to have those skills?'

I thought it was fascinating, and emotionally as well if there are tragedies or traumas or moments in your past ancestors’ lives – are they passed onto you? So that idea of a person who's sort of floating in life in the contemporary, who then starts to understand who he is through the make-up of six or seven generations of people, I thought was really interesting. And then the legacy of, you know, you don't die; you pass onto your children your life, and that life runs in the blood, that concept and idea I thought was amazing.

Q: And what was the main cinematic challenge for you?
A: It was, "How do you bring this world to life for real?" Michael [Fassbender] did a lot of the action sequences, and got hit a lot. We were losing stuntmen, so it had a very old-school feel about it in regards that we were there wanting to do this in-camera, do little jumps and see real architecture.

We spent a lot of time going to certain locations that were hard to get to, to bring to life that texture and that grit that you just never can get with green screen, so the effort behind trying to get a world that felt believable, and that the assassins existed and it didn’t feel supernatural was really important to us.

I think it's kind of coming through the film now, and it's really interesting in terms of the contemporary world of Cal and Michael’s character and how he experiences the past. We wanted that past to feel very visceral and real, and something that was sort of imprinted in his brain.

Q: You mentioned that Michael came up to you because you didn't know anything about Assassin's Creed. In what ways did you return the favour and push him to his limits with the parkour and all the action?
A: I think as soon as I sat down and said to Michael, "How do you want to approach the physicality of the assassin?" we instantly looked at each other and went, "We want to do it for real," so he worked out for six months, and he got incredibly fit. He learnt an enormous amount of parkour: he was jumping off churches and across buildings. It's a very intense experience.

It's very different from him coming on and acting and doing the dialogue and the performance to actually put your body through that sort of gymnastics. It's really difficult, so he just got super-super-prepared for it, and it means a lot to him. He's a producer on the film. He's developed it over the last 2-3 years. He was developing it way before I came on board, so it's something that he wanted to get right. It was a real achievement, what he physically was able to do within the film.

Q: How was the experience of Michael as a producer?
A: He was just very passionate about getting the story right, and was very involved in the development of the script. It was a different relationship, but as soon as we walked on set and I was directing him as an actor, that felt very, very different from when we're off set and actually saying, “Okay, we’ve got to get this done in a week, and this part of the story's not working, what do you think?" It was a very different relationship to on the set, but really great.

Q: And your own limits?
A: Just keeping up, you know [laughs]. It's a 90-day shot, which is actually quite quick for a film like this and it just never stops – I still haven’t stopped, it's like a marathon. You have to just keep on moving forward, and I loved that about it too, because you can't grieve for what you didn’t get the day before. You just have to keep going, despite the enormity and labour of it.