A contract between engaged parties before they get married. Typically, prenups are used to protect the assets of one of the parties, especially when one of them has a large income stream (actors, rock stars, and financiers all qualify), or when one is supporting the other through school. A prenuptial agreement will typically specify which assets are not joint, what form and size alimony will take, and often custody arrangements, as well. Prenuptials can also be used to enforce activities during the marriage, including what religious institutions children will attend, and how monthly bills will be managed.

One of the more intriguing prenuptial agreements was between [William Hurt and Heidi Henderson. Having met each other in alcohol rehab, the prenup specified that Hurt's alimony payments would be increased if he started drinking again post-divorce, while they would be reduced if she started again.