In his autobiography "Vanity Will Get You Somewhere", actor Joseph Cotten referred to this film as "Under Corny Crap". Supposedly he had also done so on set, invoking Hitchcock's ire; intentionally or otherwise, the director did not use him again for six years.
Margaret Leighton appeared with her future husband Michael Wilding in this film. After their marriage in 1964, they worked together several more times, but, by his own admission, Wilding preferred retirement and was happy just to be a supportive audience member for his wife. In this film, Michael Wilding played Charles Adare and Margaret Leighton played Milly.
According to Michael Wilding's autobiography "The Wilding Way", on one occasion while Ingrid Bergman and Michael Wilding were in the middle of a passionate love scene Hitchcock let out a howl of pain, then in the most gentle tone said "Please move the camera a little to the right. You have just run over my foot." The X-ray revealed later that the camera's weight had broken Hitchcock's big toe.
Hitchcock began to use the "Ten Minute Take" of continuous one-reel shooting which he had enjoyed refining on his previous film Rope, but as the process proved far more difficult here than in the enclosed apartment-set drama, only a couple of sequences were ultimately shot for the finished print.
Jack Cardiff (Cinematographer of this film) mentioned about his cinematography and the long take technique of this film in the documentary "Cameraman: The Life and Work of Jack Cardiff (2010)."
This was third film in a row that failed at box office. His previous box office failures were The Paradine Case (1947) and Rope (1948). Alfred Hitchcock's film Stage Fright (1950) after this film was also a box office failure.
Near the end of a long continuous shot, as Sam Flusky (Cotton) leads his guests into the dining room, a set of candlesticks wobble on the table...perhaps caused by one of the guests bumping the table or by an unseen stage hand moving equipment to complete the shot.
Alfred Hitchcock:
about five minutes into the movie in the town square wearing a coat and a brown hat. Ten minutes later he is one of three men on the steps of government house.
The trivia item below may give away important plot points.
With Alfred Hitchcock, Playwright James Bridie wrote the screenplay for this film in such a way where four main characters (Lady Henrietta, Milly, Charles Adare, and Samson Flusky) are alike through their actions.