With a scar inflicted by a sword-wielding princess, Ed Sheeran’s guest appearance in Game of Thrones could be seen as fiction mirroring reality.

The injury, reportedly incurred during a knighting prank mix-up last year, could have come straight from the pages of George R.R Martin’s cult fantasy epic. However, the show’s executive producers, David Benioff and D.B Weiss announced at a South by Southwest festival panel discussion that the real reason for the booking was as a surprise for Maisie Williams, who plays Ayra Stark in the show.

“For years, we tried to get Ed Sheeran on the show to surprise Maisie, and this year we finally did it,” they said.

Other guest stars have included members of Coldplay, Mastodon, and Sigur Rós. Often, however, the cameo roles are heavily disguised and unrecognisable. It is not clear what Ed’s role will be or whether he will be killed off – like so many of the show’s former characters.

The singer tweeted a link to one of the reports from the panel discussion, saying “Looks like the cat’s out of the bag”.

“OMGGGG THIS IS THE BEST NEWS OF 2017” one fan tweeted, in typically restrained fashion.

Game Of Thrones returns in July.