In 2017, musician Ed Sheeran appeared in an episode of Game of Thrones. It was the episode "Stormborn" from season 7. Arya Stark was riding towards King's Landing, on her way to kill Cersei Lannister. She stops to visit with a group of friendly Lannister soldiers, none of whom are fans of the city. One of them is played by Ed Sheeran, who we hear off-camera singing a song:

Honestly, I always liked this scene. It humanizes the everyday soldiers on the ground, making us think twice about automatically associating Lannisters with evil and greed; these guys aren't high-born, they're just peasants hired by the Lannisters to fight in a war they likely won't benefit from. But at the time, the scene got a lot of attention because Ed Sheeran was in it. There was some snarky chatter online that he was too distracting.

Vanity Fair asked Sheeran about the cameo recently...