Meet the very first actor to be killed off in Game of Thrones

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“And then obviously I died within five minutes.”

You see, Rob hadn’t been cast in just any show. After months of auditions, he’d picked up a part in Game of Thrones, the smash-hit epic that later became a word-of-mouth sensation over eight seasons and made massive stars out of its huge cast.

However, it was also a show that made a habit out of gleefully murdering said cast at every turn, which is why poor old Ser Waymar found himself at the wrong end of a White Walker spear in the first scene of the series’ very first episode.

Since then, the series has continued to make a name for itself by killing off its main characters including Sean Bean’s Ned Stark, Richard Madden’s Robb Stark and Pedro Pascal’s Oberyn Martell among dozens of others, regularly traumatising fans with their shock exits – but it all began with Rob, who played the very first character killed onscreen in Game of Thrones.

“I didn’t really realise the significance until they really started killing off all these big characters in the way the show’s famous for,” Rob (who has since appeared in various plays and TV shows and had a regular role in Holby City) tells me. “And then I sort of realised – ‘Hey, that’s quite amazing, isn’t it?’”

“I’ve sort of dined out on it a little bit. It’s in my Twitter bio.”

In another life, perhaps Rob’s Thrones experience could have been even more significant. Like almost every young actor his age, when he heard that HBO was casting for a big new fantasy series he quickly tried to get in the running, auditioning for several major parts in 2009 for what would have been the pilot episode for the series.

“There was quite a lot of buzz about it all, and excitement,” Rob says. “Films in that genre like Lord of the Rings had been very successful, but there wasn’t really a TV show like it at the time.”

And when they started, the auditions were head-spinning. One day, he might be called in for a two-episode character, the next a role that would last two years. Another audition could be for a character that would last a series – another would see him locked into a contract for five years.

“Eventually, I got close to a couple of the more major roles and didn't get them, sadly,” Rob says now. “I read for Jon, I read for Theon, and almost all those male parts at the beginning.”

With no part won, that might have been it – but after the infamous first Game of Thrones pilot went down poorly (one of the notes given to showrunners David Benioff and DB Weiss was simply “change everything”) Rob got another chance, with the production reshooting or scrapping 80% of what they had and recasting Ser Waymar after the original actor - Harry Potter's Jamie Campbell Bower, coincidentally now about to star in a Game of Thrones prequel - was unavailable.

“I did come back about six or seven months later or however long it was, and auditioned for a few of the smaller roles and they were very nice, and just kept getting me back in,” Rob says.

“And eventually, they found something that fitted for me, which was great. It was a nice one to get actually, because we were opening the show, and it was so separate it was like we were doing our own short film.”

Even for a smaller role in Game of Thrones, and even in the years before the show became the cultural phenomenon it is now, shooting the series was quite an undertaking. Rob had to learn how to ride a horse from scratch, and all in all the seven-minute scene took around two weeks to shoot in September 2010, with a sizable crew of behind-the-scenes craftsmen working hard on the sequence.

“They were filming it in a forest about an hour outside Belfast,” Rob recalls. “One side was sort of normal forest, trees. And then on the other side, they just carpeted the whole of it with fake snow.

“It looked absolutely incredible. Just being in that environment was amazing. It was great, it was just so much fun.”

Still, despite the pressure – reshooting the pilot had to have been costly, and Thrones was an expensive series even then – Rob says the whole experience of filming the doomed Night’s Watch expedition was actually fairly laid back, with plenty of time for the actors to ease into their roles.

“We were quite lucky because the snow was constantly in our scenes, and they took ages to get that right,” he explains.

“So you had a lot of time to warm up into every shot. And we had a very nice director, Tim Van Patten, who was just very reassuring and complementary.

“You think there's going to be huge pressure on these things, but they're often very relaxed, and very pleasant and jolly. It was great! I think everyone was pleased to be there.”

The finished scene sees Rob’s character Waymar Royce lead a small expedition of the Night’s Watch beyond the icy Wall, where he and his sworn brothers (played by Bronson Webb and Dermot Keaney) look for missing wildlings and instead run into the deadly White Walkers of legend.

In George RR Martin’s original novel (specifically the prologue to A Game of Thrones) the arrogant Waymar then reveals a hidden bravery, inviting the Walkers to “dance with me” and holding them off before being murdered and turned into a blue-eyed wight – but the TV series kept things a little simpler, allowing Rob’s character to see the Walkers for the first time just before they cut him down.

“In an extra bit we filmed I got sliced in two,” Rob reveals, “and we had that thing you sometimes get in horror films and fantasy shows, where one part of your body goes one way and the other part goes another way.

“You never know why these things are in or not. But I think they said they just didn't want it to be too heavy, that first little section, they wanted things to be hinted at more than completely explicit.”

And with that cut (both literal and editorial), Rob was done with Game of Thrones. Or so he thought – because while he didn’t really keep up with the series initially (he says he needed a break after all the auditioning, but is now up to date) it definitely caught up with him.

Online, many fans fondly reminisce about the appearance of “Matt Damon” (aka Rob) in the opening shot of the series, comment on his Instagram posts with Game of Thrones questions or discuss the differences between Ser Waymar in the books compared to the show, and even in real life Rob’s still approached by fans from time to time.

“I'm doing a play at the moment and people still come along at the stage door with photos from it for me to sign,” Rob tells me. “People get obsessed with shows like that and want every single actor's autograph.

“It’s not a huge stream of people, but I’ve got it every so often over the years. It's really nice, it's not oppressive.”

Now, though, even this attention could be coming to an end. Game of Thrones’ final series is approaching, with just six episodes left before we wave goodbye to Westeros for good (or at least until that spin-off gets going), and a terrible battle between the living and the White Walkers is coming that could send a whole load of beloved characters to join Ser Waymar in the ground (including his father Yohn Royce, played by Rupert Vansittart in the series).

“That White Walkers strand of the story has become the story,” Rob says, “so I still feel quite a strong link to it.

“In a way our scene was setting up some of the themes that appear in the rest of the series – the arrogance of some of the characters, and the stakes of the real threat. It was a great little piece to do, in the context of the whole show.

“It's going to lead to the final scenes of the whole series, I imagine, that White Walker stuff,” he added. “My overall emotions are to be really proud and pleased to be involved with any show like that, even in a tiny way.

“I can only imagine what the people who have been working on it for however many years will feel now it’s ending. It must be extraordinary.”

In any case, whatever happens in season eight Game of Thrones fans have definitely learned one thing over the course of the series. Valar Morghulis – all men must die – and that means someone had to get the ball rolling. Rob, for his part, is happy for that to be his legacy.

“It's always something I'll look back on and be really proud of,” he tells me. “It’s a real honour in a way.

“All those characters are brilliantly written – they’re so fun to play because you get to be dismissive and arrogant and high status and cocky, and all those kind of things you normally try and avoid being in real life. But you get a license to do it in Game of Thrones.

“And you get the brilliant sword, and the cloak, and you're on a horse. This is great!” he laughs.

“It's just fun. I have really fond memories of the whole thing.”

Rob Ostlere’s book The Actor’s Career Bible is on sale now

The final series of Game of Thrones will air on 15th April at 2am and 9pm on Sky Atlantic and NOW TV