King Ralph (1991)

John Goodman is Ralph Hampton Gainesworth Jones, an overweight Las Vegas lounge singer who finds out he's a distant relative of the British royal family and next in line for the throne after a freak accidents wipes everyone else out in King Ralph (1991). Also in the cast are noted thespians Peter O'Toole, John Hurt, and Joely Richardson. And at about the 20-minute mark, we get to see a brief nip-slip Camille Coduri that will put a royal scepter in your pants.