Kit Harington discusses release of his new film

Kit Harington plays Jon Snow in HBO's Game of Thrones. Picture: Helen Sloan

He’s also a little fed up of advising people about abs – he played a gladiator in Pompeii earlier this year “and that was gym six days a week, and eating 4,000 calories a day” – but his most recent sporting activity was a set of tennis lessons, undertaken for a Wimbledon mockumentary called 7 Days in Hell, where he plays a British tennis prodigy opposite Cuckoo’s Andy Samberg. Has he based his character on Andy Murray then? “I can’t really tell you that,” says Harington, apologetically. “I think I’m allowed to say that I worked with Andy Samberg on it, but he won’t let me say anything else, because he wants to keep it quiet until it goes out.” Can he at least say how the tennis went? “Put it this way,” he says. “We have doubles.”

Harington has also been muzzled as to whether raven-haired, sloe-eyed Jon Snow survives the next gory season of Game of Thrones, but he is happy to talk about his new film, Testament of Youth, a heartbreaking dramatisation of the memoirs of nurse, feminist and scholar Vera Brittain, and the men she lost to the First World War, including her fiancé Roland Leighton, played by Harington.

In the past Harington has also been shy about discussing his family because the conversation tends to dwell on his father’s posh family tree, which includes King Charles II and Henry Dundas, first Viscount Melville, on its branches, but now he rather enjoys recounting family war stories, including a general on his father’s side (“my father says he was a good general, so I hope that he was”), and a great-grandfather from his mother’s side who was a doctor at the Front. “He won a medal for going out into the field and saving a lot of men ‘under trying circumstances’.” Harington pauses to consider this citation. “It’s funny how understated they were then. It makes you think the circumstances must have been more than trying.”

Harington has always been fascinated by this period of history. “The Second World War was just as important, and just as horrific, but in 1914 this scale of warfare was all new. The huge losses – and the huge misunderstanding back at home about what was happening in battle.” At school he chose to study the war poets, Robert Graves, Siegfried Sassoon and Wilfred Owen. For Testament of Youth, he also read Roland Leighton’s poetry.

“It’s good, if undeveloped, but if he had lived I think he would have gone on to great things. That’s the pity of it, when you consider the war poets of the time, and of course all the young men who lost their lives. Such a lot of talent, which never got a chance to reach its potential.”

He also read the love letters between Vera and Roland: “There’s a strong sense of a feisty aggressive girl, who didn’t want to be romanced by men. And you know what, Roland loves that, and he deals with her so charmingly. And of course they talk a lot about their future together, which is very poignant. Yet at the same time you read their big statements to each other about Life and Heroism, it reminds you – they were only 19.”

Harington is almost a decade older than his character, having turned 28 at Christmas. What was he like at 19? “A bit like Roland,” he says, immediately. “I was confident about what I thought and said – maybe a bit arrogant. I was a year into drama school, and was pretty sure of myself. I’d thought about acting when I was 12 or 13 but at first it seemed a silly profession.”

He looks up at me, a little shy, or perhaps ironic. “I thought I should be a journalist instead. But although I liked writing, I wasn’t really doing a lot of it, whereas I was always in plays. So I realised that really, acting was where my passion lay.”

Harington’s first job after graduating from the University of London’s Central School of Speech and Drama in 2008 was also rooted in the First World War. Aged 22 he landed the lead role of Albert Narracott in the Royal National Theatre’s production of War Horse.

He auditioned for Spielberg’s version, but Jeremy Irvine got the part (“I was too old”). However, around the same time his agent sent over a script for an American TV pilot, offering medieval adventure, R-rated sex and violence. Harington had never read George RR Martin’s books, and was unimpressed by the dead cat of a hairpiece that was supplied for the pilot. Yet there was something about Game of Thrones that prompted the studio to reshoot, and pump in a bit more money, launching a global phenomenon of swordfights, political power plays, just-hatched dragons and an enormous cast of complicated characters, including Harington’s Jon Snow, a warrior usually brooding under layers of beard and fur.

The hair this time was Harington’s own unruly set of curls. It now has its own contract, forbidding him to cut it short. For Testament of Youth, they had to pack it down on to his skull, and pull a shorter-back-and-sides hairpiece over the top.

As he points out, television has become a much more powerful platform for actors since he joined Game of Thrones in 2011. Mainstream film-making recedes from risk, but TV producers are still prepared to gamble on edgier material like Game of Thrones, or Breaking Bad, while the character arcs for TV series are bigger and more complex.

“HBO has become this desirable thing,” says Harington. “Great directors and writers are moving into TV. The taboo of being a ‘TV actor’ has disappeared, and doing Thrones opened doors, offered movies and meant I was able to choose things, instead of taking whatever I was given.”

The first series paid off his student loan. By series four it has bought him a house, a nice BMW, and the chance to travel to far-flung countries, without fretting at the cost. On the other hand, he is never far from someone shouting: “You know nothing, Jon Snow.”

“That’s the thing about Thrones, it has a global reach. There hasn’t been a place on Earth I’ve been where I haven’t been recognised. I was in South America recently and we had queues of people outside the hotel waiting to take photos.”

On the whole he doesn’t mind the fame aspect – “usually people are quite happy to see you and that’s a nice way to go through life” – but he doesn’t particularly enjoy the selfie craze. “I find it really refreshing when someone just wants to come up, shake my hand and tell me they like the show. For me that’s a nice interaction.

“A photo is just proof that you met me, and often you’re too busy worrying about the picture to just enjoy the chat. Camera-phones are destructive, and I do wonder about the camera-phone generation. People watch everything through this little screen – they go to concerts, and they film it. If there’s a live event on the streets at the Edinburgh Fringe, then they film that. I wonder what that does to our memory.”

I tell him that Steve Martin used to fend off autograph hunters by giving them a card saying they had met him, and found him agreeable. Harington, delighted, applauds. “One of my friends, who is also an actor, has started to say, ‘I don’t do photos, but I will give you a hug’. I’m thinking of taking that one up myself, because it shows you care about the interaction, and you appreciate the person without ruining it with a selfie.”

Fandom works both ways of course. It’s unlikely George RR Martin watched Channel 4 News much before writing his bestsellers, so it must be pre-coincidence that the UK now holds two famous Jon Snows. Channel 4 even got the two of them together for interview last year. The older, taller Snow looked amused. The younger fictional counterpart was plain delighted.

“I was,” cries Harington. “I love that guy! He was the reason I wanted to be a journalist to be honest.” Did you tell him that? “After the interview, I did. I said, ‘I’ve loved you and idolised you all my life – and now here I am, a completely different Jon Snow’!”

• Testament of Youth is on general release from Friday