"For years, we tried to get Ed Sheeran on the show to surprise Maisie, and this year we finally did it," Benioff said during a panel discussion at the South By Southwest festival in Austin, Texas, alongside Weiss and stars Sophie Turner and Maisie Williams.
Details concerning Sheeran's involvement with the show were not discussed.
On Twitter, Sheeran commented on the announcement writing, "guess the cats out of the bag."
Sheeran is the latest musician to guest star on the show following Coldplay's Will Champion and Snow Patrol's Gary Lightbody who have appeared in previous episodes.
Also during the panel, Benioff and Weiss announced that the eighth and final season of Game of Thrones will contain six episodes, one less then the upcoming seven episode Season 7.
While discussing the future and the possibility of continuing the series in a spinoff, the duo mentioned they would not be involved with Benioff stating, "I think its better for them to get new blood in with new visions."
Game of Thrones Season 7 is set to premiere on HBO on July 16.