Musicians in the band on the soundtrack included bassist Jack Bruce and Burt Bacharach on piano.
Many of the Italian cast members have been dubbed by British equity members such as Irene Handl, Robert Rietty, Grégoire Aslan, Roger Delgado, and Nikki Van der Zyl among others.
The actor portraying Moses (in the Biblical epic being filmed by Vittorio De Sica in the desert) has a hairstyle modeled on Michelangelo's renowned sculpture, "Moses"; horns are sculpted into the actor's hair, mimicking the horns in Michelangelo's statue (placed there due to a mistranslation of the Bible, in which the Hebrew word for "rays" was misread as 'horns').
When Harry Granoff (Martin Balsam) is trying to make a phone call to Rome when he's drunk, he has a miscommunication with the operator. He finally says to the operator, "No, not Roma. Rome!" Six years later, director Federico Fellini (who is parodied by Peter Sellers in this film) made a film called Roma (1972).