“THERE will be blood.”

That’s a suitably menacing promise from the most intimidating man in Game of Thrones, Hafthor Bjornsson.

When he’s not competing in strongman competitions, working out or eating to maintain his outrageously powerful frame, the two-metre-tall, 180kg Bjornsson plays The Mountain in HBO’s hit show. He’s currently in Australia to promote his work with SodaStream, aimed at reducing the damage plastic bottles do to the environment.

Bjornsson isn’t allowed to reveal much about the remaining episodes of season six, but in an interview with news.com.au, he said enough to whet the appetite of the show’s impatient, bloodthirsty fans.

MORE: Hafthor Bjornsson has never been this huge

You see, we’ve been conditioned to expect violence from Game of Thrones — crave it, even — and the events in King’s Landing this season haven’t delivered. The Mountain, who’s walking around the city as a reanimated corpse, has only managed to brutally murder one person. It’s all very anticlimactic.

That’s why Bjornsson’s promise that there “will be blood” before the season ends is so exciting. He’s an authoritative source, because he’ll probably be the one spilling that blood.

The last time we saw The Mountain in a proper fight, he certainly spilled a lot. It was at Tyrion’s trial by combat, where he crushed Oberyn Martell’s skull with his bare hands. That’s the scene for which Bjornsson is most famous.

“I remember when I was filming that scene, squishing the fake head. Even the fake head was so real that it felt very uncomfortable,” he says.

“With the crowd, and the people behind the camera, it felt so real. I remember, filming the fight, I got so into it.”

The dramatic confrontation between two masterful fighters took a lot more work than most viewers realise. The Mountain’s bone-crushing feat got all the attention, but the elaborately choreographed duel preceding it required weeks of practise.

“It’s a little like dancing, you know? It’s moves you have to learn,” Bjornsson says.

“I’m actually better with the physical things because I’m a good athlete. But it was always hard work. I had to put a lot of time into it, many weeks of preparation for that fight.”

And the challenges kept coming for Bjornsson as he filmed season six. The Mountain, having been raised from the dead, had to look particularly zombie-like.

“I had to wear a mask a lot. That’s hard work. It’s like being in a sauna the whole day because you’re wearing big armour with a helmet and then the mask. Not nice,” he says.

However, The Mountain’s greatest challenge may still be ahead of him. If you believe a popular fan theory — and this writer is very much on the bandwagon — he could face off against his own brother, Sandor Clegane. We asked Bjornsson — very hypothetically — who would win that fight.

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“Obviously I would win,” he says. “Look, I’m half man, half zombie. I’m supposed to be a lot stronger now than I was before. So obviously, I would win.”

Fair enough. Hopefully we’ll find out for sure sooner rather than later. But one way or another, there will be blood.

You can read more about Hafthor Bjornsson’s work to help the environment with SodaStream here. And be sure to watch Game of Thrones next week, in case he kills someone.