I was just reading about the movie Stalag 17. It said that in the movie, even the actors in the cast didn’t know who the stoolie was until near the end of the shooting.
But the movie was based on a successful Broadway play that had just been staged a year or so earlier. They even had some of the actors from the Broadway show in the movie.
Billy Wilder and Edwin Blum adapted the play’s script for the movie. Did they change the ending so it was different from the play? If so, who was the stoolie in the Broadway play?
No, they didn’t change the ending. I’ve got a copy of the play. Wilder and Blum added some scenes , played up the comedy parts, and made some minor character changes, but they didn’t change the ending or the spy. They DID minimize the ethical question (“should we throw this guy out there with cans tied to him as a decoy, and it’s certain he’s going to get shot?” In the film, there’s no question about it), and where they hid the guy they were spiriting away (in the rafters over the latrine, not in the water tank). I have no idea why they’d claim the actors didn’t know.
The guys who wrote the original play, by the way, had been POWs. It gave the play a realistic edge.
It was supposedly the actors themselves who said it: In a featurette made later, members of the cast said that they themselves did not know the identity of the informant until the last three days of shooting.cite I’m assuming this is Stalag 17: From Reality to Screen which was a bonus feature on the Special Collectors Edition DVD.
Wilder probably told those who were in the play not to give away the ending. The other actors, who probably did not see the Broadway play,* would have no idea. Wilder could also tell everyone, “we’ve changed the ending a bit.”
*In the 50s, a trip from LA to NYC was still a big deal, and people didn’t make it routinely.