Pat Boone didn't want to make this film, but his agent talked him into it. Years later, he said he's glad he did it because of the regular residual checks, and it's the movie he'll probably be best remembered for.
James Mason reportedly had very little patience with Arlene Dahl's "movie star" preening. Their relationship off-screen was very much like their relationship on- screen.
(at around 1h 35 mins) Count Saknussemm says: "I don't sleep. I hate those little slices of death." This is a variation of an Edgar Allan Poe quote: "Sleep, those little slices of death; Oh how I loathe them".
Fox gave the green light to this big-budget CinemaScope production partially due to the success of 20,000 Leagues Under the Sea (1954) and Around the World in 80 Days (1956). As with those earlier films, the heavy cost proved to be a good investment, resulting in a big hit at the box office.