Marlene Dietrich has a cameo as a guest at the Blue Angel nightclub. One of Dietrich's most famous films is The Blue Angel.
The main actors, Franchot Tone and Jean Wallace, were married in real life.
The film features cameos by numerous Hollywood stars, such as Henry Fonda (a waiter at the Blue Angel), Marsha Hunt (a secretary), Burgess Meredith (a bartender who joins Malloy for a drink), Everett Sloane (a liquor delivery man), and John Garfield (a man outside Agostini's building).
Barbara says her previous cat was called Hadrian VII. This is a reference to the extremely eccentric novel Hadrian VII, by Frederick Rolfe, about an Englishman who becomes Pope and reforms the Church.
Franchot Tone and Jean Wallace would divorce only a few months after making this movie.