Adapted from the novel "The Show Must Go On" by Gerald Verner.
The auditorium scenes for the Regency Theatre were filmed at the former Granville Theatre of Varieties on Walham Green (now Fulham Broadway) in London. Built in 1898 by prolific theatre architect Frank Matcham it closed in 1950, and was altered to serve as a film, then television studio from 1955 to 1968. The Beatles did a television special there in October 1964. Outrage at its demolition in 1971 was instrumental in motivating legislation to protect other historic theatres and cinemas.
The outside views of the theatre are actually of 'The Palace Theatre', Shaftesbury Avenue where, at present, 'Harry Potter and the Cursed Child Parts 1 & 2' are currently showing to huge success.
In The Astonished Heart (1950), Noël Coward and Margaret Leighton go to the theatre. The play they see is "Tread Softly".