(at around 35 mins) Christopher Reeve bowed out just before filming began. He was slated to make a cameo as Superman, but was unavailable. The film still features a picture of Reeve in costume in a brief cameo.
The film's opening credits cost almost $1 million to shoot.
Peter Cook would later complain of Faye Dunaway's diva behavior on this film and her constant lack of punctuality resulting in delays. At one point the producers even considered replacing her with Anjelica Huston or Jane Fonda.
Almost 85% of the film was shot on giant sound stages at Pinewood Studios.