Britain's Prince Harry delighted the London cast of hit musical Hamilton and its creator Lin-Manuel Miranda on Wednesday (August 29) when he sang the first note of King George III's song 'You'll Be Back'.

The surprised cast could be seen laughing and applauding as Prince Harry turned to Miranda and said: "That's definitely not going to happen. He (Miranda) did try but I said no."

Prince Harry and his wife Meghan attended the special performance to raise money for Sentebale, a charity he set up with Prince Seeiso of Lesotho, which works with children affected by HIV in southern Africa.

Addressing the audience at the end of the performance, Miranda joked about writing a comic version of Prince Harry's ancestor.

Hamilton is an unconventional take on the life of Alexander Hamilton, one of the founding fathers of the United States, blending, hip-hop and rap, rhythm and blues and ballads.

The London production, housed in the refurbished Victoria Palace Theatre, is the show's first foray outside of the United States after successful runs in Chicago, San Francisco and Los Angeles as well as Broadway in New York.