King Ralph

King Ralph is a 1991 American comedy film starring John Goodman in the title role of Ralph Jones. The movie also stars Peter OToole as the Kings private secretary, Sir Cedric Willingham, Camille Coduri as Ralphs girlfriend Miranda Greene, and John Hurt as the British peer Percival Graves, who schemes to get Ralph removed in order to claim the throne himself.

The entire House of Wyndham based on the House of Windsor, the ruling family of the United Kingdom in the film, is electrocuted in a freak accident while posing for a family photograph, after a cable becomes wet during a storm. The British government immediately begins a search led by courtier and royal private secretary Sir Cedric Willingham to look for any surviving heirs to whom to pass the crown. A researcher finally locates a living heir named Ralph Jones, an American rock and roll musician.In Las Vegas, Ralph, an easygoing slob, works as a lounge singerpiano player in one of the main casinos. Duncan Phipps and Inspector Thomas McGuire watch the performance and applaud with enthusiasm, while Ralph discovers that he has been fired for watching American football on TV when he ought to be focusing on playing piano, then replaced by a chimpanzee. Ralph meets Phipps and McGuire, who inform him that he is now king, though at first Ralph thinks this is some prank. Phipps explains that Ralphs grandfather, the 2nd Duke of Warren, was engaged in a brief affair with a hotel maid while visiting the States, and this affair produced a child, Ralphs father. But since his father and grandfather have died, Ralph is the only surviving Wyndham heir. Ralph is finally convinced when seeing the Dukes ring, an exact copy of a ring his grandmother claimed to have been given by a prince. ........

Source: Wikipedia