Pun Salad

This is #182 on IMDB's top-250 list, and, to my mind, utterly deserves to be there, or even higher. Even today, it's an unusual blend of comedy and keen suspense drama. And the comedy is a mix of broad mugging and subtle wit. Billy Wilder's involved.

Everybody's really good in this. William Holden (an Oscar-winning performance) is the guy everyone else hates, because he's a successful capitalist in the eponymous German POW camp, and everyone suspects him of being a spy for the Krauts. Except, of course, the actual spy for the Krauts, who is … nah, if you don't know, go rent it. Holden is able to turn the tables on the bad guy in a very satisfying denouement.

The immortal Harvey Lembeck also turns in perhaps his finest performance here. Otto Preminger, ditto. And from IMDB:

The uncredited soldier singing at the Christmas Party is Ross Bagdasarian, also known as 'Dave Seville' , the leader/creator/voice of 'Alvin and the Chipmunks'.