When Robert Mitchum got fed up with repeated re-takes in which director Otto Preminger ordered him to slap Jean Simmons across the face, he turned around and slapped Preminger, asking whether it was this way he wanted it. Preminger immediately demanded of producer Howard Hughes that Mitchum be replaced. Hughes refused.
At first Otto Preminger refused to direct this movie, because he hated the script. The normally reclusive Howard Hughes personally picked up Preminger in his car and persuaded him to make the movie. "I'm going to get even with that little bitch," Hughes told Preminger, referring to Jean Simmons, "and you're going to help me." He gave Preminger permission to rewrite the script, and promised him a bonus if he could finish the picture in 18 days. By that time Simmons' contract with Hughes would have expired.
Prior to a 6/21/11 airing on TCM, Robert Osborne revealed that this was the final film of Jean Simmons under her contract with Howard Hughes--he'd bought it without her knowledge from J. Arthur Rank Studios in England. Her displeasure led her to cut her hair off, knowing that Hughes preferred long-haired leading ladies and thinking it might prevent him from utilizing her before the contract's end date. Instead, he put her in this film and she was given a wig to wear throughout. He also promised director Otto Preminger a bonus if he finished shooting before Simmons' contract expires, which he collected.
Diane's Jaguar XK-120 had a MSRP of $3,940 in the USA (about $40,200 in 2017). In all, about 12,000 were made from 1948 to 1954. In excellent condition, at auction in 2017, that car could fetch well into six figures.