A premarital agreement is one signed by parties in anticipation of marriage. A postnuptial agreement is one signed after marriage and is governed by all the same laws.
Virginia Code Section 20-155 states that “married persons may enter into agreements with each other for the purpose of settling the rights and obligations of either or both of them, to the same extent, with the same effect, and subject to the same conditions, as provided in §§ 20-147 through 20-154 for agreements between prospective spouses.”
Virginia requires that both parties either be unmarried or married when the agreement is signed, meaning one spouse cannot sign pre-marriage and the other sign post-marriage.
If the signing is not conducted properly, the agreement will not be enforceable. Both spouses should sign in front of a notary public, so that validity of the signatures will be presumed.