The Icelandic folk band was recently photographed in costume on the set in Girona, Spain, where they were apparently filming inside the Sant Pere de Gallivants monastery.

In images revealed by fansite Watchers on the Wall, singer Nanna Bryndís Hilmarsdottir can be seen, while another photo shows drummer Arnar Rosenkranz Hilmarsson in sunglasses on the Spanish set.

O Monsters and Men are not the first musicians to guest star on the show - Sigur Ros, Mastodon, Coldplay's Will Champion, and Snow Patrol's Gary Lightbody have all had cameo appearances.