Review: 'A Royal Night Out' Starring Sarah Gadon, Bel Bowley, Rupert Everett, And Emily Watson

By mixing “The King’s Speech” with “Roman Holiday,” “A Royal Night Out” is likely to become your mother and grandmother’s new favorite movie. We promise that we mean no offense to either the matriarchs in your family or this charming movie. This British trifle of a film imagines what happened to Princesses Elizabeth and Margaret Windsor on V-E Night in 1945. Historical details are thin on what really happened to the young women the evening their father King George VI delivered his historic address, so “A Royal Night Out” fantasizes their exploits with fun period detail.

The film begins with black-and-white newsreel footage of the war’s end, cutting to a similarly toned image of Elizabeth’s observant face. Played by Canadian actress Sarah Gadon (“Enemy,” “Belle”) with an accent that sounds perfectly upper-class British to these American ears, she’s a prim princess of 19. Elizabeth is well aware of her future as the country’s monarch and the responsibility she bears. Younger...