The daughter of playwright Robert Courtneidge starred with Jack Hulbert in what 1940 musical comedy film?
Under Your Hat: Under Your Hat is a 1940 British musical comedy spy film directed by Maurice Elvey and starring Jack Hulbert, Cicely Courtneidge and Austin Trevor. Cicely Courtneidge:  The daughter of the producer and playwright Robert Courtneidge, she was appearing in his productions in the West End, by the age of 16, and was quickly promoted from minor to major roles in his Edwardian musical comedies.
Under Your Hat