Lady Behave! (1937)

It's bad enough that Clarice Kendall Andrews, Paula's irresponsible sister, comes home from celebrating Mardi Gras and drunkenly mentions that she got married during the festivities. What's worse is the fact that Paula knows that Clarice is still married to an equally irresponsible gigolo. Paula learns that the man Clarice married, Stephen Cormack, has skipped the country and his lawyer, thinking that Paula is Clarice, offers the older woman $5000 to annul the marriage. Paula's lawyer convinces her to pretend she's Cormack's husband until he can get Clarice's marriage annulled. Paula moves into Cormack's house and discovers he has two teen-aged children who consider her a gold-digger after their father's fortune. Meanwhile, Clarice's husband refuses to have their marriage annulled and tries to blackmail Paula into giving him to $10,000 for his silence.