Throughout the filming, Doris Day became increasingly concerned that Sir Alfred Hitchcock paid more attention to camera set-ups, lighting, and technical matters than he did to her performance. Convinced that he was displeased with her work, she finally confronted him. His reply was, "My dear Miss Day, if you weren't giving me what I wanted, then I would have to direct you!"
At first Doris Day refused to record "Que Sera, Sera" as a popular song release, dismissing it as "a forgettable children's song". It not only went on to win an Academy Award, but also became the biggest hit of her recording career and her signature song. She sang the same song in two more movies, Ne mangez pas les marguerites (1960) and La blonde défi le FBI (1966), and it was used as the theme song for all one hundred twenty-four episodes of her television series, Que sera sera (1968).
It was during the making of this movie, when she saw how camels, goats and other animal extras in a marketplace scene were being treated, that Doris Day began her lifelong commitment to preventing animal abuse. She was so appalled at the conditions the animals were in that she refused to work unless they were properly fed and cared for. The production company actually had to set up feeding stations for the various goats, sheep, camels, et cetera, and feed them every day before Day would agree to go back to work.
Doris Day was so popular with the British that when she arrived at her London hotel for location shooting, mobs of fans had gotten word that she would be staying there and had gathered. Pandemonium erupted when they saw her, and she needed a police escort to get in. Fans continued to surround the hotel, camping out, shouting her name, asking for autographs, and hoping for a chance to see her. The hotel management finally had to ask her to leave.
Doris Day had a fear of flying ever since touring with Bob Hope in the 1940s and enduring some close calls in impenetrable winter weather. She almost turned down her role in this movie because it required travel to London and Marrakesh. Her husband and manager, Martin Melcher, talked her into accepting it.
Bernard Herrmann: Conductor plays himself on-screen. Walking to the Albert Hall, Josephine McKann passes by a billboard naming the conductor of the London Symphony Orchestra, and the mezzo-soprano soloist Barbara Howitt of the Covent Garden Opera Chorus. Both are in opening credits for the "Cantata Storm Clouds". This movie may be the only surviving movie of the (uncredited) Orchestra's Leader, violinist George Stratton, and Principal Cello Dennis Nisbett.
Alfred Hitchcock: In the Moroccan marketplace in a crowd watching the elevated acrobats with his back to the camera, on the extreme left, immediately before the murder. Be alert and look quickly because the viewer's eye is naturally drawn to the acrobats.