Emerging from the Blood Gate of the Tower of London, the musicians and actors combined for a sword performance.
The choreography took more than two months to plan.
The crowds had been expecting to see the Changing of the Guard from the Coldstream Guards with the marching classic, The Standard of St George March, before the troops suddenly switched to the TV show's theme tune.
The Night’s Watch - a military order who defend The Wall in the Game of Thrones kingdom - approached the British ceremonial parade from the doldrums of the Tower.
Twelve actors were transformed into The Night’s Watch for the performance, by a team of stylists and make-up artists, wearing custom-made and specifically-designed costumes that took ten weeks to create.
The squad of Night’s Watch foot soldiers then took to the main parade ground outside the Waterloo Barracks at the Tower.
The last defence against Westeros, as they are known in the television series, then displayed a specially choreographed march and battle-cry to the theme tune played by the Band of the Coldstream Guards, before disappearing back into the darkness of the Tower.