Blond Cheat is a 1938 American romantic comedy film directed by Joseph Santley and starring Joan Fontaine, Derrick De Marney, and Cecil Kellaway.

The screenplay is by Harry Segall, Charles Kaufman, Paul Yawitz, and Viola Brothers Shore.

[1] Michael Ashburn (Derrick De Marney) is the chief assistant to Rufus Trent (Cecil Kellaway), a wealthy London loan broker.

As Michael is closing the shop late one afternoon, a man named Douglas (Olaf Hytten) takes out a large loan, using earrings worn by his niece, Julie (Joan Fontaine), as a deposit.

He scurries right off with the money but, to his dismay, Michael finds that the earrings are fastened to Julie's ears and cannot be removed.

He hails a policeman to have her put in a jail cell so that she's kept somewhere safe, but when the cop arrives, she tricks him into arresting Michael instead.

Her "uncle" runs the agency and she quickly removes the earrings as he praises her night's work.

In reality, Julie is an actress and, with her successful work breaking the engagement between Michael and Roberta, is offered a leading role in a new production.

Trent, upset that the wedding is still on, goes back to Douglas and tells him he won't pay until the engagement is broken for good.

Alone with Michael, Julie confesses that she was trying to break up his engagement on purpose that night because she didn't think he should be married simply because he comes from a prominent family.