Who would win in a fight between the British Army and the Night Watch?
We'll never know, but the two forces just came eye-to-eye at the Tower of London.
The video, promoting Game of Thrones Season 8, features the Coldstream Guards oom-pah-pahing the show's stirring theme tune.
A dozen members of the Night Guard then shamble into view. They jeer at the proper soldiers, then draw their swords on the crowd. The crowd, in return, draws a phalanx of smartphones to record the spectacle. A two-eyed raven looks on.
It's all a bit cringey. Some might question whether Her Majesty's Armed Forces should participate in a PR stunt for Sky Atlantic. Others will find it all a bit of a laugh. We only hope this muster of a ragtag border patrol is not a foretaste of Brexit Britain.
Game of Thrones Season 8 is on Sky Atlantic from 15 April. Insert obligatory play on the phrase 'Winter is coming' here.