Vittorio Gassman is not listed in the on-screen credits even though he plays the male lead in the "Two Against One" segment and his name and picture appeared on US posters for the film.
Natalie Wood reportedly turned down the leading roles.
Lord Lucan was screen-tested for the role of a gambling English aristocrat.
During production the film was titled "Woman x 7", but was changed somewhere along the line because it sounded too much like the sort of 'cloak and dagger' picture then very much in vogue.