Christopher Lee was originally considered for the role of Count Karnestein (probably to make the film marketable for fans of his Hammer vampire films) but the part eventually went to his friend Mel Ferrer.
Director Cameo: Roger Vadim (passenger on the airplane).
The film was screened at the White House on 20th September 1961 - in his journal aide Arthur Schlesinger described the film as 'terrible' and related that President Kennedy left after 40 minutes, saying he would be content to read Schlesinger's review (he also wrote film criticism).
Italian censorship visa # 33435 delivered on 25 November 1960.