The Duke of Sussex chimed in for a short singing performance at the Hamilton charity gala on Wednesday.

Prince Harry briefly took over the role of King George III, his sixth great grandfather, in singing a line from the crowd-favorite “You’ll Be Back.”

Prince Harry took the performance in stride, cutting the song after singing “You say,” jokingly adding at that “That’s definitely not going to happen” to raucous laughter from the audience. Motioning towards the shows award-winning creator, Lin Manuel-Miranda, he noted, “He did try, but I said ‘no.’”

Joining Prince Harry was his wife, The Duchess of Sussex, Meghan. The charity event raised £300,000 for the couple’s HIV charity, Sentebale, which was founded by Harry in 2006.

The charity aims to improve the lives of impoverished children in Botswana and Lesotho, and Harry thanked the audience for contributing to his philanthropic cause. Part of the purpose of the charity is to halt the generational stigma of hand-down HIV and to bring awareness to people throughout the world.

Hamilton is a world-famous musical that tells the story of American revolutionary and founding father Alexander Hamilton. King George III provides comic relief to the story, arrogantly strutting around the stage and bemoaning the loss of the colonies as they revolt and reject his authority.

The role of King George is currently played by Michael Jibson in the London production, and he stood by as Prince Harry took the stage to sing the king’s signature song “You’ll Be Back.”

Jibson tweeted a video of the song after the play, joking that this was the “moment I was upstaged.”

Miranda mingled with the London crew, telling the story of the creation of Hamilton with the crowd. He noted that he created the King George character during his honeymoon years ago, and showed awe and appreciation that he was now sitting in the same room with his actual sixth great grandson.

“You don’t often get a direct descendent” to watch the show, he told reporters during the event. It was clear Miranda found this to be quite the surreal experience.

Meghan and Harry have seen the performance before, having attended it earlier in the year. Meghan also viewed the original performance on Broadway in 2016, attending the show with actress Priyanka Chopra.