Tom Bowen (Fred Astaire) and Ellen Bowen (Jane Powell) are a brother and sister dance team from New York. Their agent (Keenan Wynn) books them in London for performances during the time of the royal wedding. Aboard a cruise ship to London, Ellen becomes involved with aristocrat and playboy, Lord John Brindale (Peter Lawford). In London, Tom meets and falls in love with Anne Ashmond (Sarah Churchill), a dancer in his show. Despite a few minor complications, it all ends happily as the two couples find love and marriage on the day of the royal wedding.
Royal Wedding is famous for several dance sequences, including a classic number in which Astaire appears to dance on the ceiling and walls of his hotel room. Jane Powell proves to be an elegant and athletic partner for Astaire; though perhaps his best duet of the movie takes place with a hat rack he discovers on the cruise to England. This is one of Astaire's best and I highly recommend it.
The music for Royal Wedding was composed by Burton Lane, who is best known for his work in Finian's Rainbow (1947) and his Grammy Award-winning On a Clear Day You Can See Forever (1965). Lane's greatest musical accomplishment may very well be his discovery of an 11-year-old singing phenom named Frances Gumm, whom the world now knows better as Judy Garland.
The high point of Royal Wedding is the Ceiling Dance in which Fred Astaire appears to literally dance on the ceiling and walls of his hotel room. The effect was accomplished by putting the whole set inside of a 20-foot diameter rotating cage with fixed camera mount. As the cage turned, Astaire would seamlessly dance across the four sides of the box, creating the illusion of weightlessness. The same technique would later be used to create the illusion of a zero gravity environment in 2001: A Space Odyssey.