'Game of Thrones' theory says the White Walkers will return in the final episode

As we edge ever closer to the day of the last-ever episode of HBO's hit show Game of Thrones, we are coming across all kinds of elaborate fan theories about how the series will end.

Some of them are quite plausible and a credit to the viewers' ability to spot subtle clues, while others are little more, erm, farfetched.

But one particular theory, courtesy of Reddit user TurntCrawdad, does have credibility as it picks up on a potentially crucial detail that many seem to have overlooked.

Take a look at the preview for Sunday night's finale episode:

TurntCrawdad's theory suggests that the White Walkers - who were supposedly wiped out as a direct result of Arya slaying the Night King - might not actually be gone after all.

You see, as the Redditor points out, the supposed decimation of the White Walkers at the hands of Arya, doesn't account for Craster's sons who had supposedly been turned into White Walkers.

In season two, it emerged that Craster had been sacrificing his newborn sons to the White Walkers.

Based on this, TurntCrawdad suggests that Gilly's baby Little Sam - who Craster was supposed to sacrifice to the Night King in earlier episodes of the show - may have some White Walker blood.

This is the epic moment Arya Stark conquers the Night King:

"As we know, GRRM’s writing is often influenced by the works of famous historical writers, as well as history itself. When I was reading about Gilly, I came to understand that her name originates from the real-life plant known as gilliflower/gillyflower," TurntCrawdad writes.

"Gilliflower is mentioned in Shakespeare’s ‘A Winter’s Tale’, in which they are cross-fertilized by humans, rather than by Nature: I have heard it said/There is an art which in their piedness shares/With great creating Nature … I’ll not put/The dibble in earth to set one slip of them’."

"I’m almost certain that this is a subtle clue that might strengthen a suggestion that Gilly and Little Sam have White Walker blood in their veins," the viewer concludes. "It also made me wonder whether the NK came to Bran/3ER at Winterfell not to kill him, but to take ownership of his property – namely Little Sam."

Could this really mean we haven't seen the end of the White Walkers? Well, I guess we'll just have to tune into Sunday night's finale episode to find out!