(Musical) Two Girls on Broadway - Lana Turner, Joan Blondell, George Murphy 1940

https://www.imdb.com/title/tt0033191/ Eddie sells his song to a Broadway producer and also lands a job dancing in the musical. He sends for his dance partner-fiancée Molly who brings her younger sister Pat. Upon seeing Molly and Pat dance, the producer picks Pat for the show and gives Molly a job selling cigarettes.