First a Girl on AllMovie

British musical star Jessie Matthews tops the bill in this song-studded comedy. Elizabeth (Matthews) is a delivery girl for a seamstress who is dispatched to drop off some costumes at a theater where a noted female impersonator is about to open a new show. The star is suddenly stricken with laryngitis, and Elizabeth is drafted to take over in his place, posing as a man who dresses like a woman. Elizabeth is a hit, and with Victor (Sonnie Hale) as her manager, she sets forth on a concert tour of Europe; she continues to perform as a man and draws packed houses and enthusiastic reviews. However, a mysterious Princess (Anna Lee) and her significant other get the strange feeling there's something odd about this new singing star, and they're determined to find out what it is. First a Girl was adapted from the German film Viktor und Viktoria, which would be remade into the American musical comedy Victor/Victoria.