'Game of Thrones' writer reveals what The Night King's sigil actually means. Read here

Still having nightmares about that bit in the Game of Thrones season 8 premiere when little Ned Umber's dead body, which was pinned against a bunch of severed limbs, suddenly woke up and started screaming? Us too.

You may also have lost a few hours' sleep wondering why the disembodied parts were arranged into a lovely spiral pattern by the White Walkers. Well, the premiere's writer Dave Hill has now revealed what the terrifying sigil means, and it probably won't help you get to bed, to be honest.

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Speaking to the New York Post in a wide-ranging interview, Hill explained: "As we saw with Bran and the Three-Eyed Raven, the spiral pattern was sacred to the Children of the Forest, who created the Night King by sacrificing a captured man in a spiral 'henge of stones'."The Night King then adopted the symbol as a sort of blasphemy, like Satan with the upside-down cross."

We’ve seen the ominous-looking sigil numerous times before. In season seven, episode four, titled 'The Spoils of War', Jon shows Daenerys the carvings on the walls of the caves beneath Dragonstone. They were inscribed there by the Children of the Forest and represent the period in which they united with the First Men, despite both factions being at war for centuries, to defeat the White Walkers.

We also saw the symbol in the very first episode when the Night’s Watch came across a group of Wildlings who had been slaughtered by the White Walkers.

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And again in season three, when Jon Snow found the severed remains of the Night Watch’s horses laid out in the same pattern.