You can see where this is going, can’t you? Harington stumbled, fell and earned himself a prolonged spell on crutches that caused him to miss a promotional trip to Comic-Con and “pretty much ended [his] summer”. Thankfully, his bosses at HBO saw the funny side.

“They were very lovely and far more supportive than I deserved them to be,” he chuckles. “But, I mean, they hired a really fun-loving group of actors and it was only a matter of time before one of us did damage to ourselves.”

That Harington had cause to raise a celebratory glass or three goes without saying.

Just under two years after it first hit screens, the TV adaptation of George RR Martin’s intoxicatingly expansive fantasy saga has grown from raved-about cult hit to fully-fledged fire-breathing phenomenon.

There are multiple tie-in cook books offering trenchers of roast hog. There are Twitter-storming online memes that determine which ancient family you would belong to and, last month in the US, the Series 2 box set became HBO’s biggest seller since, well, the Series 1 box set.

“It really was always a shock to me that it became this huge success,” admits Harington. “Personally, it was such a big thing to be part of an HBO pilot, that the idea of the show actually doing well was neither here nor there. That I got the role and it went on to become a series was big enough, but it just kept escalating.”

INTO THE WILD

And things have escalated in more ways than one. Year 2 ratcheted up the action with multiple claims to the throne in the Medieval England-like land of Westeros, grisly beheadings, cinematic battle scenes, an often baffling array of new characters and fresh locations, plus a climactic CGI vista of the marauding maggot-eyed undead.

And this year? More new characters (swelling the number to more than 100), pubescent dragons, shock deaths, preposterous sex scenes, more great lines for Peter Dinkladge and a meatier role for Harington’s character Jon Snow – the bastard child of the heroic Stark family who, until now, has been notable mainly for his membership of monastic black-clad enforcers the Night’s Watch, sullen attitude and Timotei-lustrous locks.

However, things are different this time. One of the most intriguing new plot threads in Series 3 (of the planned eight) is Snow’s deep-cover mission – think The Departed with frozen beards and patchwork tents – in the midst of a band of cudgel-wielding, libertarian savages known as the Wildlings. Needless to say, it wouldn’t have served to have him hobbling around on a knackered ankle.

“I was always looking forward to this part of the story because of that idea of being a spy and dealing with all the issues a spy has to deal with,” says Harington. “It’s that age-old question of where a spy’s loyalties lie. We’ll have to wait and see what he does.”

ICELANDIC INSULATION

Born with the grand moniker Christopher Catesby Harington – he assumed Kit was his official name until one embarrassing day at school when he was 11 – to a former playwright mother and businessman father, Harington hails from London, which explains the fact that in real life he doesn’t speak with Jon Snow’s gravy-thick northern accent.