Knightfall star Tom Cullen talks Templar training, on-set injuries and his leading man philosophy

Tom Cullen's historical epic Knightfall has been receiving rave reviews for its dramatic season finale across the pond, but for UK viewers awaiting the second season's premiere on 2 July, all the thrills and spills are finally here to stay. Welsh-born Cullen shot to fame in award-winning independent film Weekend, before capturing mainstream attention with roles in Downton Abbey, Gunpowder opposite Kit Harington, and Genius.

But it has been Cullen's powerful performance as noble Knight Templar Landry in HISTORY's Knightfall that has catapulted him to leading man status both on screen and on set. Now back on UK screens for its second season, viewers can expect the historical epic to reunite old friends and enemies, with plenty of battle scenes worthy of the four-month special training the cast had to endure.

As we join the series, a disgraced Landry must fight his way back to good standing within the secretive and deadly Knights Templar, even as the King of France prepares a monstrous army to wipe out the powerful order forever. Here, Cullen tells Tempus how he approaches leadership status on set, and how the show's extreme training methods became an intense bonding experience for the cast – including Star Wars icon Mark Hamill…

Tom, what can you tell us about returning to Knightfall for series two?
It feels really good to be back. We film in Prague with such a really great gang of people, cast and crew, so it was great to get together and carry on telling the story. This season takes a very dark, authentic and gritty look at the Templars during that period, but it's still a lot of fun and doesn't take itself too seriously. The scripts are really fantastic. It's a great season; I'm so happy to get it out there!

With any show like this, there is an element where have to use markers of history to inform the story, but the fun part is interpreting the gaps in between. Ultimately, it's about entertainment, and I hope it will inspire people to find out more about the Templars, because it's a fascinating period of history. They were such a clandestine sect, and there's really very little we know for sure about the inner workings of the temple. My character never existed, but we do have real life characters like Jacques de Molay, a very famous Templar, in this series.

Did you know much about the Templars before you joined the series?
I was actually really interested in the Templars beforehand. I was a bit of a history nut as a kid, and I'd always loved the iconography of that period. You know, films like The Last Crusade and then when Sean Connery turns up at the end of Robin Hood: Prince of Thieves, I thought it was so cool. So when this opportunity came up, I loved the idea of exploring that part of history. I was surprised that this story strangely hasn't ever really been told, especially since we're definitely feeling the repercussions of that time even today. >>

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Your brother Joseph is also in the cast this season. What was it like working together?
He is! You know, when we were kids we used to run around making films and pretending to be knights. So it was pretty wild to find ourselves side by side on a battlefield, being on a massive film set with hundreds of extras. It was difficult not to look at each other and just pinch ourselves.

The battle scenes are pretty epic. How do you prepare physically for the role?
It's definitely the most physically demanding job I've ever done. We film for anything from 12 to 18-hour shoots. The costume weighs 23kg, and after a few hours it really starts to weigh you down, so you have to be physically able to carry that, to start with. Then you add the fact that you're constantly fighting or running or, you know, getting the crap kicked out of you. So you have to be really physically fit just to kind of get through the six months.

And then there's the other element, which is that you need to look like a knight – I mean, the Templars trained for six hours a day. In order to reach that level of physical fitness the cast runs a bootcamp for about four weeks before shooting, where we're trained by Czech former MMA fighters. They basically beat the hell out of us until we're crying in a pool of sweat and blood in the corner – it's a lot of fun!

That sounds intense! Have you suffered any injuries?
It is intense! But it's a great bonding experience for the cast – we're all actors who've never really done anything like that kind of training, so it's a really great way of forming fast friendships that ultimately, I think, translates itself to the screen. I haven't been too injured during training, but I did break my two big toes on the second day of filming. The thing about television is that it's a huge machine, and it doesn't stop for anybody. So you just have to kind of get on the train and carry on going, because if you don't you get left behind. Everyone picks up these small bumps and bruises, and a couple of broken bone here and there, but we all know just how lucky we are to do what we do.

As a leading man on a project of such scale, do you feel pressure to be a leader among your castmates? Do you have a leadership philosophy?
It's funny that you asked about leadership, because this is actually something that's really important to me. Film sets can often be out of kilter with society – there's an obvious hierarchy on set, which I always really struggled with. Having worked with 'Number Ones' before who haven't maybe been the nicest people, that can permeate a set in a way that's quite unhealthy. So the one thing I try to do is make sure the Knightfall set is the most egalitarian environment that it could possibly be. I always treat everyone, from the runner or the guy that's making breakfast, exactly the same as I treat our producers and directors. I think that creating that level of respect and decency is essential for a healthy working environment. And it's great, because everyone's really bought into it and become really close friends. >>

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You have a real knack for picking stand out projects. How do you choose your roles?
I think it's always a bit of a gamble. I mean, Downton Abbey, Gunpowder are such different projects. I started seven years ago with the film Weekend, and when I began I was just super grateful to be acting at all. I chose projects based on whether the character and story excited me. But now, I think what I really like to do is scare and challenge myself. I don't want to be pigeonholed, and I have a broad spectrum of taste. My biggest passion project is a small, independent film I've written and directed, but I love being in these big historical epics as well.

Could you tell us more about your directorial debut?
It's called Pink Wall and just premiered at South x Southwest festival. It stars Tatiana Maslany and Jay Duplass, and is a relationship drama set over six years. We shot it in nine days on a micro-budget. It's had really, really great reviews and we've sold it for distribution in the UK and US, so I'm really excited for it to come to cinemas – though I can't share much more about that yet! It's a simple film, but I'm very proud of it. And it was a dream come true to be able to direct.

Is there a project that you feel changed your career?
I think the film that really changed my life was Weekend. Until that point I had a lot of self-doubt about whether I could make it as an actor, whether I was good enough, but it was director Andrew Haigh's first film and he saw something in me. It was a tiny, British film shot on a micro-budget, but it was a great script and director. None of us expected it to do so well, but it received incredible recognition, and so obviously raised all our profiles. But in terms of how it changed my life, I think it gave me the confidence and belief that I could go for more. Acting is always an up-and-down journey, but I think that will always be the job about which I'm most proud.

Knightfall season 2 premieres on Tuesday 2 July at 9pm exclusively on HISTORY