We last encountered Billy Wilder in Sunset Boulevard. He was having Gloria Swanson, as Norma Desmond, watch one of Norma’s old silent films, only it was one of Gloria’s — Queen Kelly.

Wilder pulls a similar trick in his 1957 courtroom thriller, Witness for the Prosecution, in which Tyrone Power plays Leonard Vole, a World War II veteran in London who has landed in a spot of trouble. We learn in flashbacks that he’s invented a newfangled egg-beater and has been trying to peddle it, without much luck. That is, until he and Mrs. French (Norma Varden), a wealthy widow, meet cute in a shop where she’s buying a smart new hat, and he commences a flirtation with her. I didn’t mention that Leonard is married; his wife, Christine, is played by Marlene Dietrich.

I pause here to say that one of the more mysterious things about Witness for the Prosecution is Vole’s nationality. A commenter on IMDB says that William Holden was Wilder’s first choice for the part, and that Gene Kelly, Kirk Douglas, Glenn Ford, and Jack Lemmon were considered before Power, also an American, accepted. He makes no effort to do an English accent, and at least one book on Wilder takes Vole to be an American. Yet the script — by Wilder, Harry Kurnitz, and Larry Marcus, based on Agatha Christie’s play — makes no mention of his not being British, and even gives him some Britishisms to say.

Three of these appear in the movie-in-movie scene. Discouraged by a lack of eggbeater interest, Vole repairs to a cinema. Who should sit in the row in front of him but Mrs. French, her hat obscuring his view of the shoot-em-up Western on the screen? He invites her to sit next to her, and explains, “That chap on the white horse is called Jesse James. Those others have led him ambush. It’s not at all cricket.”

The film they’re watching was made in 1939 and is called Jesse James. The title character (not discernible in the Witness for the Prosecution scene) was played by Tyrone Power.