The final season of Game of Thrones is going to include an epic battle scene cast and crew worked hard to film over 55 nights in a row in Northern Ireland.

When the final season of Game of Thrones premieres on April 14, fans will be anticipating some epic scenes ahead, and perhaps none will be more epic than the season’s major battle. While we don’t yet know if it will be the North and Danerys against Cersei, all of humankind against the Night King and his Army of the Dead, or some combination of all of the above, we do have information pointing to it being above and beyond any battle the series has featured before.

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The battle was filmed over the course of 55 straight nights in Northern Ireland. That’s nearly two months of the cast and crew filming a marathon production, at Magheramorne Quarry and Toome in Co. Antrim, in brutal weather conditions.

Assistant Director Jonathan Quinlan shared on social media a thank you note from the show’s producers to the cast and crew for such a Herculean effort. It read: “This is for the Night Dragons. For enduring 55 straight nights. For enduring the cold, the rain, the snow, the mud, the sheep shit of Toome and the winds of Magheramorne. When tens of millions of people around the world watch this episode a year from now, they won’t know how hard you worked. They won’t care how tired you were or how tough it was to do your job in sub-freezing temperatures. They’ll just understand that they’re watching something that’s never been done before. And that’s because of you.”

The note that the #GameofThrones producers gave to the cast and crew after filming for 55 straight nights

— Game of Thrones Facts (@thronesfacts) April 7, 2018

How cryptic! What could it be that’s “never been done before”?

Read More: Travel through the land of Game of Thrones in Northern Ireland

Quinlan shared a photo of the thank you note on Instagram last year and then deleted it a few hours later, but not before fan sites got a hold of them.

For comparison, Game of Thrones’ most recent epic battle, from season six’s Battle of the Bastards episode, took 25 days to shoot - that’s less than half the time. The episode reportedly cost a whopping $100 million to film and the battle necessitated 600 crew members, 500 extras, and 70 horses.

We can only imagine how much bigger this battle will be!

Read More: Game of Thrones wraps up filming in Belfast 

How do you think Game of Thrones will conclude? Tell us in the comment section or on social media.

Still from the Game of Thrones Battle of the Bastards episodeHBO