James M. Cain, whose story "Two Can Sing" was the basis for this film, had himself trained as an operatic baritone. Opera figures prominently in several of his other stories, including "Serenade" and "Mildred Pierce" (though the opera parts of the plot of "Mildred Pierce" were dropped in the film version).
When Nunnally Johnson remade the picture as Everybody Does It he used the exact same script without doing any rewriting.