This early Billy Wilder film (his third) is a fairly respectable wartime effort ... performances by Anne Baxter, Akim Tamiroff and especially Erich von Stroheim are solid, the story is intriguing, and they did a nice job using California locations to replicate north Africa. It follows a British soldier trapped behind enemy lines, forced to impersonate a German spy to avoid capture.
When I first saw this film back in the late 60's I remember being engrossed by the plot and the rather inventive little twist from which the title derives. On rewatching it still works but Franchot Tone's light comic performance often interferes with the film's attempts to build tension and suspense. I suspect Wilder's original choice (Cary Grant) might have been able to pull this off with more grace and subtlety. Even so, this is a fairly worthwhile war film in most respects, focusing more on straight narrative with a minimum of wartime propaganda and stereotype.