Trivia

Many historians believe that George III's mental state was caused by porphyria, a metabolic imbalance that can cause blue urine. However, recent research into his written correspondence suggests bouts of mania, and a common type of medicine at the time could have caused blue urine, leading some to conclude that he had a psychiatric illness.

Sir Nigel Hawthorne, a stage and television actor, had little movie experience. He was so determined to reprise his award-winning stage role on-screen that he took the part of Dr. Raymond Cocteau in Demolition Man (1993) to prove that he had screen presence. Hawthorne was the producers' automatic choice for the lead. Alan Bennett only agreed to his play being turned into a movie if Hawthorne was cast as George III.

In this movie, King George III briefly mentions Pitt's drinking habits to Queen Charlotte. In the source play, as Alan Bennett puts it, "Pitt takes a swig from a hip flask, such a regular feature of his behavior, it is not noted in the stage directions." The historical Pitt was considered a heavy drinker even by 18th century standards, especially as he got older. Modern biographers agree that his alcohol intake probably contributed to his early death.

In real life, the Prince's illegal marriage to Maria Fitzherbert ended in 1794, about five years after this movie's events. They later reunited for a while after his disastrous marriage to Caroline of Brunswick.

When Willis first restrains King George III in the restraint chair, the music that plays is George Frideric Handel's "Zadok The Priest", commissioned for King George II, and performed during his and every subsequent coronation. As the music reaches its climax, the King is fully restrained in the "throne", with a leather strap around his forehead as a diadem. The music establishes the restraint scene as a mock coronation and enthronement.

Alan Bennett: The Member of Parliament who begins his speech "No-one, Mr. Speaker, entertains a higher regard for His Majesty than I do..." is the author of the original play and the movie script.