Full Moon

After rehearsing together, and then acting together, they decide to live together as well; which is fine until Crystal, another actress, tells Cathy that David is "playing around"

At the same time the question of who is paying for Cathy's apartment comes up. It happens to be her father, an army colonel, but Cathy (who is not miffed with David) lets him believe that she is being kept by an older man, a rich toy manufacturer with an invalid wife

When Cathy's father arrives unexpectedly the plot thickens hilariously: David is bundled unceremoniously out of the apartment; he jealously shadows them when they go off to the Rainbow Room

Cathy's father grows suspicious; and Cathy, to her chagrin, finds out that David's reputed "affair" was actually a visit by his younger sister

In time each of them figures out what the other is up to, but acts as if he (or she) didn't, which keeps the laughs coming right up to the final scene, in which love and good sense triumph, and marriage is the happy outcome