According to Elaine Parker's biography of Price, the actor spent breaks in location filming trying to teach the Austrian crew how to play cricket using a ball made from tape and a bat improvised from something found by the props department.
Ivor Novello approved the cast and supervised the production.
Opening credits prologue: VIENNA 1910
The set for the Theater An Der Wien was at that point one of the largest ever built at Elstree.
The original stage production opened at the Theatre Royal, Drury Lane, London on March 23 1939 and ran for 187 performances. At the outbreak of war it went on tour, returning to the Adelphi Theatre from March 14 1942 for 969 performances until July 1944, making it the most successful wartime show in London. Ivor Novello played the lead in both productions.