When Yellowstone star Kevin Costner and Christine Baumgartner announced their divorce in 2023 after 18 years of marriage, the headlines weren’t just about Hollywood heartbreak. They became a real-time lesson in what happens when one spouse decides to fight a premarital agreement in court and what the consequences of that fight can be. As California Certified Family Law Specialists serving San Diego County, some of the most common questions we received about premarital agreement challenges are as follows:
Q: Can a premarital agreement actually be challenged in court?
Yes, but it’s difficult, and the bar is high. In California, premarital agreements are presumed to be valid and enforceable as long as certain formalities were met when the agreement was originally signed. The spouse seeking to invalidate the agreement bears the burden of proving that something went wrong at the time it was signed or that at the current time the agreement is unconscionable. Simply not liking the terms years later is not enough.
Q: What grounds did Christine Baumgartner use to challenge the Costner prenup?
Christine argued that she felt pressured to sign the agreement and that she didn’t fully understand its terms. Kevin’s legal team pushed back hard, pointing out that the prenup itself stated in all caps that she had signed it “voluntarily” and “free from duress, fraud or undue influence” and that she had previously admitted she entered the agreement of her own free will. The court was not sympathetic to her position.
Q: What are the legally recognized grounds to challenge a premarital agreement in California?
Under California’s Uniform Premarital Agreement Act, the recognized grounds include that the agreement was not signed voluntarily, that there was inadequate financial disclosure before signing, that the agreement was the product of fraud, duress, or undue influence, or that specific terms are unconscionable at the time of signing or at the time of enforcement of the agreement. Claiming you didn’t understand what you signed without clear evidence of that is generally not sufficient, especially if you had the opportunity to consult independent legal counsel.
Q: What is a “no-challenge” clause, and how did it affect Christine’s case?
A “no-challenge” clause or in terrorem clause in a premarital agreement prohibits a party from trying to challenge the agreement’s validity for any reason and if they do, they lose whatever they would have been entitled to under the agreement. Usually, in California such a clause will not be enforceable because one should always be able to challenge any agreement based on fraud, duress or lack of voluntary consent. However, the court in the Costner divorce upheld the validity of the prenup and Christine was concerned about continuing her prenup challenge and when she learned she could be required to repay the $1.5 million payout and cover Kevin’s attorney’s fees if she lost, she settled quickly. In California these clauses are powerful tools, and not every attorney knows how to draft them properly.
Q: Can you only get what is in the prenup, if anything?
No. Despite the prenup being enforced, reports indicate Christine received somewhat more than the agreement’s stated terms as part of the negotiated settlement. This is not unusual. Even when a prenup holds up, the parties may choose to resolve their divorce on terms that go slightly beyond the four corners of the document, simply to avoid the time, cost, and uncertainty of continued litigation.
Q: What’s the takeaway for someone with a premarital agreement in California?
First, if you have a premarital agreement, don’t assume challenging it is a viable strategy. The Costner case shows how quickly that approach can backfire especially when the agreement was drafted with protective provisions like a no-challenge clause and both parties are represented by counsel.
Second, if you’re considering entering a premarital agreement, the quality of the drafting matters enormously. A poorly drafted agreement is far easier to attack. A well-crafted one with proper financial disclosure, independent counsel for both parties, adequate time before the wedding, and carefully considered provisions is extremely difficult to undo.
Q: How can Primus Family Law Group help?
At Primus Family Law Group, Bonnie A. Rabinovitch-Mantel is recognized as one of San Diego’s leading attorneys in drafting and litigating premarital agreements. As a California Certified Family Law Specialist with over two decades of exclusive family law experience, she understands exactly what makes these agreements hold up in court and what makes them vulnerable. Whether you are looking to draft an agreement, enforce one, challenge one or understand your options when facing one in a divorce, our team brings over 50 years of combined experience to every case we handle in San Diego County.