Albert Finney was initially asked to reprise his role as Poirot from Murder on the Orient Express. However, he had found the make-up he had to wear for the first movie very uncomfortable in the hot interior of the train, and on realizing that he would have to undergo the same experience, this time in temperatures exceeding 100 degrees Fahrenheit, he declined the role.
David Niven as Colonel Johnny Race boards the Karnak wearing a straw boater hat with a Royal Green Jackets hat band, and later in the film wears a Royal Green Jackets necktie. The Royal Green Jackets (formed in 1966) were, at the time the film was made, the descendant regiment of Niven's wartime regiment the Rifle Brigade.
Barbara Hicks who has a blink-and-you-miss-it role as a schoolteacher turned up in Evil Under the Sun made by the same producers. She also features in a couple of Joan Hickson 's Miss Marple television programs as Miss Hartnell.
The trivia items below may give away important plot points.
The song Jackie is singing in the lounge just before she shoots Simon is "Frankie and Johnny," a folk song about a woman who shoots her lover after discovering that he is cheating on her.