A pretty standard plot, well executed. Sylvia Sidney is delightful in her dual role Most of the supporting cast is fine except, surprisingly, Cary Grant who, while not bad, is still finding his way a bit as an actor. And Vince Barnett who's Count Nicholaus becomes tiresome.
Preston Sturges' script here (written with Frank Partos) is a precursor to his own later The Lady Eve, where he improves the material (even though he later refuses much credit for this film). But Sidney and Grant are both charming in these roles, and there's plenty of good humor that's not re-used later to make this one worthwhile.