Image copyright Helen Sloan-HBO / The Hollywood Archive

This article contains spoilers for Game of Thrones season eight episode three

It's taken eight years, 70 episodes and thousands of deaths to get us to this moment.

The epic fight between the living and the dead in Game of Thrones was shown in the UK on Monday.

The episode, called The Long Night, lasted 82 minutes and took viewers on a rollercoaster journey featuring our favourite characters.

HBO - the makers of the fantasy drama - has now released a behind-the-scenes video giving some of the secrets of how it all came together.

This article contains spoilers - obviously.

The episode involved 11 weeks of night shooting

The cast and crew filmed for 55 nights straight in Belfast to produce The Long Night - often working from 6pm until 5am.

Emilia Clarke, who plays Daenerys Targaryen, revealed it was -14C during the shoot.

"It's too cold to snow. When it's too cold to snow you know you've got trouble," she says.

Three weeks into the shoot, many of the cast and crew looked like they were part of the army of the dead.

"People looked slightly haunted," says Jacob Anderson, who plays Grey Worm.

"Everybody looked like, 'This is getting into us. It's getting into our spirits'."

Director Miguel Sapochnik adds: "Look at it this way - I never ever want to do that again. I don't think anybody that did that wants to do it again."

But they all agree it was worth it.

Maisie Williams, who plays Arya Stark, said: "It was a mammoth task that we were faced with and we did it.

"It feels incredible. That first week after the night shoot the crew were smiling at the sun."

Arya's heroic act has been planned for three years

Image copyright HBO/YouTube

The plot of Game of Thrones is always a well-kept secret - with only a few people knowing how the drama will eventually unfold.

In The Long Night, Arya Stark becomes the ultimate hero by using her assassin skills to bring down the Night King.

The fact it was Arya that killed the Night King came as a shock to most of the cast.

"I remember being like, 'Whoa' and applauding in my head," says Emilia.

Image copyright Home Box Office (HBO)

"And in the read through when Maisie was doing it we were all whooping and cheering. It was amazing."

But not everyone was completely happy Arya took the limelight.

Kit Harington, who plays Jon Snow, says he'd have "bet you thousands" he'd be the person to kill the Night King.

"Before we read the final script I was like, 'Yeah it's definitely me'."

The producers say that Jon has always been the saviour but this time it just "didn't feel right".

Maisie is right-handed but learned to fight with her left hand

Image copyright HBO

Maisie was told a year before the crew started filming to get her endurance levels up to scratch for her big scene.

In the Game of Thrones books Arya is left-handed - but Maisie uses her right.

She trained left-handed and producers revealed most of the fighting is done by the actress herself, not a stunt woman.

"It's one thing practising a sparring fight. But when you're fighting for your life with loads of stunt men who do this day-to-day, it's a completely different ball game," Maisie says.

"I hold the record for the most apologies on set."

The big giant is a real actor

Image copyright HBO/YouTube

This is Game of Thrones, so you know that its creators don't mind killing off characters we love.

This episode was no different, with Lyanna Mormont being crushed to death by a giant - but not before she stabbed him in the eye.

Bella Ramsey, who plays the young leader, says: "When I found out I was dying it was the best thing really.

"I decided I'd be happy if I ended up on the throne - which I thought was very, very unlikely - or I had a great death."

The producers say they wanted it to be her "heroic" moment.

And despite all the fancy technology available in 2019, they decided to go a bit old school and get an actor in for the giant.

On set VFX supervisor Eric Carney said: "Our giant performer, Ian Whyte, he's 7ft 5ins. He performed all the actions of the giant in front of a green screen.

"For the shots where he had to pick up Lyanna we put tracking markers on a green doll that he picked up and we motion captured that and used it to drive a robotic arm to pick up our actress."

Bella says it was "fitting" for Lyanna to die stabbing a giant in the eye.

"It's a bit like David and Goliath," she adds.

Samwell Tarley had to fight his urges

Image copyright HBO

Samwell Tarley is known for being a lover, not a fighter. During the battle he's seen in tears after getting overpowered by the dead.

But John Bradley, who plays the fan favourite, revealed it was a struggle to keep his fighting urges inside during filming.

"If you're involved in a battle scene, you like to see yourself as fighter and you like to make it look as good as you possibly can.

"But [director] Miguel was the one who had to keep reigning me in and say, 'Remember you're playing Samwell Tarley and he's not a fighter'.

"The reason Sam is in there is because he's not a fighter and he can show how normal people would cope."

What do critics make of the battle episode?

Image copyright Helen Sloan-HBO/The Hollywood Archive

Ed Cumming, from The Independent newspaper, describes the Night King's death as "epic, gritty, profoundly silly and surprisingly camp".

He adds: "But in terms of spectacle, it is the equal of anything to come out of Hollywood."

Stephen Kelly, from the BBC, gave it three out of five stars.

He says: "There are great moments, obviously. The episode's first act is a masterclass in fear and tension - of the feeling that the task at hand truly is impossible."

But he describes the deaths in the battle as "a hugely overhyped aspect of this episode, which in reality panned out as a series of safe and predictable choices".

Gwilym Mumford from the Guardian said the episode meant "Game of Thrones is back to sticking them with the pointy end".

But he wasn't too impressed with the Night King's last hurrah.

"The greatest threat Westeros has ever known is now a puddle of thawing ice-cubes, and the final bosses are likely to be, as one wag on Twitter put it, 'a pregnant lady and a pirate'."

Follow Newsbeat on Instagram, Facebook, Twitter and YouTube.

Listen to Newsbeat live at 12:45 and 17:45 weekdays - or listen back here.