The War Starts in Cuba(1957)

Original title: La guerra empieza en Cuba

Year 1898. When war broke out in Cuba, Juanita, a beautiful variety singer without much luck, decides to return to Spain when she discovers that her twin sister Adelaide has married the governor of Badajoz. Adelaide is capricious, vain and embarrassing, the opposite of Juanita. However, as the girls are physically identical, the singer intends to take full advantage of this situation.