Prince Harry pretends to be George III from Hamilton

The Duke and Duchess of Sussex kicked off their "autumn term" on Wednesday night (August 29) with a gala performance of Hamilton in London in support of Prince Harry's Sentebale charity, which supports youth living with HIV in Lesotho and Botswana.

The Tony and Olivier Award-winning musical, which chronicles the life of American founding father Alexander Hamilton, features one of Harry's own ancestors as a supporting character – and Kensington Palace's resident jokester couldn't resist poking fun at his family's history during the event.

After the show, Harry joined Hamilton creator Lin-Manuel Miranda and the show's cast on stage. Armed with the mic, Prince Harry sang the signature line from King George III's three musical interludes in the show, "You say..." to the audience's rapturous applause.

He quickly waved off their cheers and pointed to Lin-Manuel, joking: "He did try, but I said no." Harry went on to thank the show's cast and crew for the event and the audience for attending in support of Sentebale, for which they raised "a huge amount of money".

Harry closed with praise for the actors, noting, "I don't know how you guys do it every night, over and over again" and "that was spectacular". The Sun royal reporter Emily Andrews described the theatre's energy as "unreal".

George III is, of course, Harry's great-great-great-great-great-great grandfather, and appears in the show to provide humorous commentary on the events taking place across the sea in Revolutionary-era America. Lin-Manuel discussed the genesis of the character's inclusion in the show after the performance.

Harry and Meghan also took time to pose with the cast, with Meghan telling one member that Prince Harry sings the soundtrack all the time, according to Andrews.

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The show is reportedly the Duchess of Sussex's favourite musical. During intermission, she told Miranda how interesting it was to watch the British audience's reaction to the character of King George versus America's.

Last night's performance marked the second time Harry and Meghan saw the show together. They took in a performance in London together in February of this year, and Meghan also saw the show with her good friend Priyanka Chopra in New York.

The event kicked off a week of engagements for the newlyweds, who will attend two galas in London next week in support of charities for which Prince Harry is patron.