These words sound the same, but overdue is an adjective meaning “late,” while overdo is a verb meaning “to do too much”:
Jim was overdue to pay his phone bill, because he didn’t have enough money.
Maria may have overdone the steaks; they’re not supposed to be black.
These sentences show some of the most common uses for these words. Overdue is used mostly to describe things that have a due-date—a certain time or date when they should be completed—such as bills, homework, and job assignments. It can also be used for personal activities, where it implies that the overdue person has done something wrong:
I told him he was overdue to call his mother.
You can use overdue for anything that is later than desired or expected. Note that a person can be overdue to do something, or something to be done can be overdue:
Anthony was overdue to call his mother; the call was overdue.
Overdo, on the other hand, means to do (anything) too much, too hard, too long, too fast, etc.:
Do not overdo preparations for the party; you always buy too much.
And to overdo it has a special colloquial meaning, which you may infer:
Rita really overdid it at the party last night, and now her head feels like a soccer ball.
Overdone often describes meat cooked for too long, too much makeup or fancy clothing, or any ostentatious appearance.