Winter came to King's Cross and Waterloo stations on Monday morning as monsters from Game of Thrones cropped up to frighten commuters after the show made its long-awaited return.
Service announcements at King's Cross were followed by the programme's insistent theme tune, while White Walkers - terrifying ghouls who turn people into the walking dead - were seen prowling Waterloo.
TfL posted a picture to Twitter of a recreation of the series's much scrapped-over iron throne alongside the caption: "King’s Cross St Pancras Tube station given Stark make-over for Game of Thrones #GoTS7."
It showed staff posing on a convincingly fancy-looking chair, one armed with a sword.
The distinctive strains of the show's theme tune were also played by a strings duo in the ticket office, flanked by Oyster machines and queue barriers.
The staggeringly successful HBO show, which follows the plays for power in a fantasy kingdom by characters ranging from the venal and sadistic to the heroic, returned last night with the first episode of its seventh and final series.
It aired in the US at 9pm local time, while keen fans in the UK were able to watch simultaneously if they stayed up till 2am Monday morning to view it on Sky Atlantic and Now TV.
Sky Atlantic will air the episode again on Monday evening at the more sociable hour of 9pm.
Evidence of the enthusiasm of King's Cross staff for Game of Thrones has been mounting for several days.
On Thursday, service announcement boards were seen bearing the word "Hodor" - a reference to the character in the series whose speech is limited to saying only that word.
By Sunday, the announcement boards had been taken over by arrows marked solely with the direction "Hodor!"
On Monday morning, passengers reported being asked over the tannoy to give up their "thrones" to others who may need it.
Some punters were unamused by the stunt, however; one Twitter user complained that tourists were blocking exits as a result.
Others simply found it all "a bit much".
"I'm a big fan of Game of Thrones, but find enthusiasm of @tfl at King's Cross Station playing the theme after each announcement a bit much!"
