Charles Laughton, who could be moody and difficult, was apparently a dream to work with, throwing himself into the role with dedication and delight. Billy Wilder later recalled a day that was set aside just for shooting reaction shots of the jury and courtroom crowd (composed of extras hired only for the day). Normally, the assistant director would read the actors' lines and the extras would react. However, Laughton, who was fascinated with the whole process of filmmaking, begged to help. So he came in on his day off and read all of the off-camera speeches for the jury members. He read not only his part, but also the judge's, the prosecutor's and even Marlene Dietrich's. According to biographer Maurice Zolotow in his book "Billy Wilder in Hollywood", the author said, "it was an exhibition of craftsmanship such as Wilder had never seen. He believes that Charles Laughton had the greatest technical range and power of any actor, man or woman, whom he has known."
Marlene Dietrich was so certain she would be nominated for an Academy Award for her performance as Christine Vole that she recorded a new introduction to her Las Vegas show mentioning her nomination. She was not nominated, and was crushed.
The press book, reviews and various articles about the production stated that the principal cast members themselves did not even know the ending of the film until the last day of shooting, when the final ten pages of the script were presented to them.
The plot deals with Charles Laughton's character recovering from a severe heart attack while defending Tyrone Power's character. In reality, this would be Tyrone Power's last complete film - he would die of a heart attack while on the set of his next film less than one year after release of this one.
When the film was released, Agatha Christie said it was the only movie based on one of her stories she had actually liked. Later, after Murder on the Orient Express (1974) was filmed, she said she liked that one too.
Charles Laughton modeled his characterization of "Sir Wilfrid Robarts," including the use of a monocle to intimidate Leonard, on Florance Guedella, an Englishman who was both Laughton's and Marlene Dietrich's lawyer and who was famous for twirling his monocle while cross-examining witnesses.
Unsure if he could convincingly play a man with a heart condition, Charles Laughton staged a heart attack in the pool one day at home. His wife, Elsa Lanchester, and a houseguest panicked and pulled him from the water, at which point he explained his trick. Lanchester's reaction has not been recorded.
Elsa Lanchester used to delight in broadcasting Marlene Dietrich's secrets. Although Dietrich was never secretive about her famous "tape lifts," Lanchester detailed their use to anyone who would listen (One of the most avid listeners was Charles Laughton, who urged a make-up man to steal one so he could try it). The lifts were stuck to the side of Dietrich's head where she wanted skin to be lifted. Then the long threads hanging from them were woven into hair at the back of her head, forcing the tabs to pull the skin very tight. A wig then covered the network of tabs and threads. Lanchester joked that Dietrich wouldn't dare to pull or twist her face for fear of loosening a lift. In the film, one can see how Dietrich rarely breaks the cold passiveness of her expression and moves her whole body rather than her head.
All of the comic scenes in the film between Charles Laughton and Elsa Lanchester were added by the screenwriters; they are not in the original play. For the 1982 television remake the adapters followed this 1957 film version nearly word-for-word and retained many of the same scenes.
While it is generally supposed that Agatha Christie chose the name Vole after the ratlike rodent of the same name, in fact the word has several other meanings also relevant to this character. In cards, a "vole" means the winning by one player of all the tricks of a game. And the expression "go the vole" can mean either to venture everything on the chance of great rewards, or to try one thing after another, usually a variety of occupations - all perfect descriptions of Christie's ingeniously named "Leonard Vole".
Marlene Dietrich's characterization of a woman desperately in love was also enhanced by her real-life crush on Tyrone Power during shooting. According to his biographer, the actor was embarrassed by her advances.
When Leonard Vole (Tyrone Power) meets Mrs. French (Norma Varden) for the second time - in the movie theater - Vole tells Mrs. French that the movie is about Jesse James. Tyrone Power starred as the famous outlaw in Jesse James (1939).
The film followed the basic story of Agatha Christie's play, but director and co-screenwriter Billy Wilder opened up the story by including numerous scenes that did not take place solely in the courtroom, as the play had, and changed the emphasis from "Leonard Vole" to "Sir Wilfrid Robarts." The character of "Miss Plimsoll" was added to the film, and the name of Leonard Vole's wife "Romaine" was changed to "Christine."
Although originally published as a short story in 1925 with the title "Traitor's Hands" by Agatha Christie, she renamed it "Witness for the Prosecution" when it was reprinted in the 1930's and 1940's in British and American publications. Her play is based on this short story.
Marlene Dietrich and Billy Wilder enjoyed a long-running mutual admiration society. She praised him repeatedly as both an artist and a human being, calling him the kindest, sweetest man she had ever known. And he once said of her, "If we had to invent someone to be the ideal woman...we would have to invent Dietrich." She threw herself into the part with gritty determination, approaching it, Wilder said, "as if she thought her career depended on it.
In her autobiography "The Lonely Life," Bette Davis said that Agatha Christie based the character of Sir Wilfred Robarts on the real-life attorney who represented Warner Bros. in her unsuccessful attempt to break her contract with them in England in 1936.
Harry Kurnitz never worked with Billy Wilder again after this film and explained why in 1964, saying the typical Wilder collaborators "have a hunted look, shuffle nervously, and have been known to break into tears if a door slams anywhere in the same building. ... (Wilder) is a fiend at work."
Less than two months after "Witness for the Prosecution" by Agatha Christie had a London premiere, it opened on Broadway at Henry Miller's Theater on December 16, 1953 and ran for 645 performances. Una O'Connor reprized her role in the movie.
According to Variety, the producers stationed guards at the doors to the soundstages. It was also said that at a command performance in London, Arthur Hornblow had managed to get the royal family to sign pledges that they would not divulge the film's surprise ending to their subjects.
The Tyrone Power character's last name is Vole. Aside from what has already been mentioned, the word "voleur" in French translates in English to burglar, embezzler, housebreaker, intruder, peculator, robber, and thief. Many of which could apply to Power's character.
Marlene Dietrich's original Cockney costume was rejected because it made her look too much like a man. So her appearance was softened somewhat, but still far enough removed from Dietrich so that audiences failed to recognize her on screen.
According to Elsa Lanchester, Charles Laughton taught 'Marlene Dietrich how to speak Cockney for the scene where she impersonates a disfigured Cockney woman. She also spent a great time at their house trying on scarves, shawls, and various wigs.