Montgomery Clift

 Montgomery Clift was signed to play Joe Gillis in ‘Sunset Boulevard’ for $5,000 per week for a guaranteed twelve weeks, but withdrew just before the start of filming, claiming his role of a young man involved with an older woman was too close to the one he had played in "The Heiress', in which he felt he had been unconvincing. An infuriated Billy Wilder responded, "If he's any kind of actor, he could be convincing making love to any woman." Clift himself was having an affair with a much older woman, the singer Libby Holman, which was suggested as his real reason for withdrawing from the film.

Forced to consider the available Paramount contract players, Wilder and producer/screenwriting partner Charles Brackett focused on William Holden, who had made an impressive debut a decade earlier in ‘Golden Boy’. Following an appearance in ‘Our Town’ he served in the military in World War II, and his return to the screen afterward had been moderately successful. Holden was enthusiastic about the script and eager to accept the role. He did not know at the time that his salary of $39,000 was much less than had been offered to Clift.

The shot of Holden floating in the pool with the policeman leaning over him almost never happened. The production crew was not prepared to shoot underwater, but a technician suggested that a large mirror be placed in the pool underneath Holden, and shot from above, giving the perfect impression they needed.

As a practical joke, during the scene where Holden and Nancy Olson kiss for the first time, Wilder let them carry on for minutes without yelling "Cut!" (he'd already gotten the shot he needed on the first take). Eventually it wasn't Wilder who shouted "Cut!" but Holden's wife, Ardis (Brenda Marshall), who happened to be on set that day.