Not so long ago, the most famous Jon Snow in the world was the revered British TV broadcaster and news anchor.
A few years ago, while attending the theatre, he passed an aspiring British actor named Kit Harington hired to greet those on the red carpet.
''Jon Snow,'' Harington, dressed as a cartoonish hotel porter, called out in excitement. ''Jon Snow!'' The broadcaster smiled at the nobody and said hello.
Now, newsreading Jon Snow's fame has been eclipsed by Harington's portrayal of bastard Jon Snow, a lead protagonist in mega-successful, mega-budget fantasy drama TV series Game of Thrones.
Harington now spends his days being similarly greeted by strangers.
''I have people doing it to me,'' he says. '''Jon Snow, Jon Snow'. It's a strange sort of parallel.''
In the flesh, without 12 layers of animal pelt wrapping his frame, Harington seems smaller than Snow, the beleaguered yet smouldering illegitimate son of Lord Eddard Stark. He manages to smoulder nonetheless.
For his new film, Pompeii, in which he plays slave-turned-gladiator Milo fighting to save his true love as Mount Vesuvius explodes, Harington worked out relentlessly, adding 12 kilograms of muscle to his lean frame. Action heroes are currently his thing.
''Well, you're always fighting against being typecast as an actor,'' he says. ''But you look at any actors in the past, they've all fit into a certain role whether it be gangster movie, whether it be fantasy action hero or whether it be romantic comedy lead.
''The next two things I do I'm going to be working very hard against my typecast. I'm moving out of the bracket of period action hero.''
When he first read HBO's pilot for Game of Thrones, based on George R.R. Martin's bestselling series A Song of Ice and Fire, Harington had no inkling it would go on to be watched by 14 million people worldwide and become one of the most pirated shows in recent history.
His only notion of the show's potency was the striking screenplay by creators D.B. Weiss and David Benioff.
''I remember reading [the pilot] and thinking, 'This doesn't sound like an HBO show,''' Harington says.
''This is a fantasy. This isn't what they usually do. Then I read it two or three times and what really struck me was how absolutely unique it was. I couldn't quite work it out. I couldn't work out what it was, what it was trying to do, what point it was making.
''I got addicted to reading that first pilot. It's a clue into why it's done well. The characters were very fully rounded, interesting individuals and I enjoyed reading them on paper.''
Snow, forever clad in ragged layers of fur and leather while surviving the biting cold of the North, is perceived as a character at odds with others.
The Starks, for whom he remains a bastard; the Free Folk spearwife Ygritte, whose allegiance to the Wildings means she shoots arrows at him despite their shared love, and, well, everyone except those who respect him in the Night's Watch.
Snow, it seems, lives in a constant state of angst.
''I'd say he's introverted and moody,'' Harington says. ''He takes himself very seriously. He takes the world very seriously. He takes his duty very seriously.
He doesn't have a lot to smile about. If you think about it, there are not many times in the script [where] it says 'Jon laughs hysterically' and 'Jon smiles'. He's not that character.''
Born Christopher Catesby Harington, the 27-year-old was called Kit because his mother liked 16th-century playwright Christopher Marlowe's abbreviated first name.
Growing up in London and Worcester, he attended the Central School of Speech and Drama in London, graduating in 2008.
In the same year, he snared the lead role of Albert Narracott in the Royal National Theatre's original stage production of War Horse; after a two-year run he appeared in Posh by Laura Wade at the Royal Court in London.
Harington acknowledges that such a stratospheric rise - from theatre graduate to stage and screen star - is rare. ''Starting off with War Horse, a leading role in a production that became a big success, was a very lucky place to find myself,'' he says.
''I would have been happy just to work and I am working and I count my lucky stars every day. About 10,000 people apply to my drama school, 30 people get in and, out of those 30 people, maybe two or three will get work. It is tiny odds and you're very lucky if you get it.''
While he cannot reveal anything about Game of Thrones' upcoming fourth series, he says it is ''a big one'' for Snow.
''He says more. He talks more. He doesn't open up about [Ygritte]. And that goes back to who he is. He's not a modern man in any way.
''This season he has to lead men and that's why he has to talk more. Usually he's been talked at and he absorbs everything. And this season he doesn't have anyone talking to him with anything like common sense. So he has to do the commonsense talking and leading of men.''
Another no-go area is the topic of Harington's ancestry.
It is no secret that Harington is descended from prominent people. His great-grandfather was Sir Richard Harington, the 12th baronet of Harington.
He is a descendant of Charles II via his grandmother, Lavender Cecilia Denny, and is also a descendant of politician Henry Dundas, 1st Viscount Melville. His great-great-grandfather, John Harington, was a 16th-century poet and inventor who conceived and built the first flushing toilet, used subsequently by Elizabeth I.
''He invented it for her, as the story goes, and she made him godson to her, which is quite interesting,'' Harington told Jimmy Kimmel Live last month.
It is also why the toilet became known as ''the john''.
What Harington is willing to reveal is that he does not know who Jon Snow's parents are, that he used a body double in season three because he broke his ankle, and that he fears flying. ''It's the complete lack of control you have over your destiny while you're in the air,'' he says.
''And also take-offs, getting further and further away from the ground I feel is very unnatural.''
Next up for Harington are two feature films. The first is World War II drama Testament of Youth, based on Vera Brittain's memoir, in which he plays a 19-year-old poet.
After that, he'll portray a modern-day spy hunting down a terrorist in the thriller Spooks, based on the popular BBC TV drama.
Both films are based in Britain - a relief to Harington after years spent on American productions based in Northern Ireland, Iceland and Toronto. Although he has enjoyed the epic settings, he is looking forward to work that does not feature being lashed by snow or volcanic ash.
''With Pompeii and with Thrones , a lot of what you're doing is fighting against bigger things around you,'' he says.
''Big castles, big sets. Everything, the elements, has to be right. The ash has to be at the right level, the snow has to be at the right level. You're constantly working alongside the elements.
"I want to do something more contained where it's about the acting. This is about the acting but it's also about everything else. It's working downwards, working small, that's the thing I want to do next.''
- Fairfax Media