On the first day of shooting, Billy Wilder made it clear that the script was to be delivered exactly as written with no deviation. He addressed this to the entire cast but with particular focus on William Holden, who wanted lines changed or added to make the character of Sefton more likeable, and Otto Preminger. The latter had a tendency to ham it up and, as a seasoned director himself, was used to calling the shots.

To achieve the build-up of suspense and the gradual revelation of character, the picture was filmed in sequence.

While filming at Paramount's ranch in Calabasas, California, Wilder reportedly wore his best shoes to work in the mud. He felt it was only fair, since he was asking his cast and crew to work under filthy, muddy conditions day after day. He even refused to use the planks that were set down for Otto Preminger's commandant character and as a result ruined his very expensive footwear.

Things that were more verbal and stage-bound in the original were worked out in more visually innovative ways during shooting. For instance, the discovery of the true informer came about on stage in an overheard conversation. On film, Wilder used the visual clue of the light cord with the loop in it.

Holden threw himself into the role with a great deal of intensity. His hair was cropped into a crewcut and his face unshaven, a look that not only gave the character reality but also undercut the actor's good looks. Usually friendly and lively on a movie set, he was withdrawn on the Stalag 17 set and complained about the noise and pranks among the rest of the cast, some of whom had an easy camaraderie from more than a year of doing the play on stage. But as his confidence grew in the role, Holden became more at ease, sometimes even frivolous, on the set.

One day during an afternoon break in filming, Holden "entertained" a young actress in his dressing room. Later that day, while shooting one of the final scenes with Don Taylor in the water tower, he looked down and saw his wife standing on the set with a stricken look on her face. Convinced she had learned about the dressing room incident, he climbed down, certain his marriage was over. He was greatly relieved when he realized she had only come to tell him she had accidentally wrecked their car.

Although suggestions for making Sefton more palatable were rejected by Wilder, the director did allow for a fleeting moment of warmth and humanity in the final scene. As he slips down into the tunnel in the barracks, Sefton says bitterly to the other airmen who had once rejected, accused and beaten him, "If I ever run into any of you bums on a street corner, just let's pretend we've never met before." That departure seemed too abrupt and anticlimactic, so Wilder had Holden pop back up through the hole, smile, and salute before disappearing again.

by Rob Nixon