The prince is set to wed his longtime love Kate Middleton on April 29, but if history is any guide, divorce lawyers say the second-in-line to the British throne would be well advised to sign a prenuptial agreement.
"It's an absolute statistical no-brainer that a prenuptial agreement would be highly beneficial in this case," said divorce lawyer James Stewart from the firm Manches, which handled the multimillion divorce case between Madonna and director Guy Ritchie.
Britain's royal family has been plagued by a string of failed marriages. Three of Queen Elizabeth II's four children have been divorced, and William's uncle on his mother's side, Charles Spencer, has two ex-wives.
Prince William's office declined to comment on whether the future king might sign a premarital contract.
Although prenuptial agreements are common in the United States, in Britain they remain rare for most couples -- never mind the royal family. British courts agreed to recognize such deals only in the last year after a slew of high-profile divorce awards gave London a reputation as the "divorce capital of the world."
Stewart said Britain's royals need to recognize that when it comes to divorce, they're just like commoners under U.K. law. And with large amounts of royal wealth most likely tied up in trusts, which can be hard to get access to, it's important to hammer out the details now just in case, he says.
"In the 21st century, there is a real need for any couple in the public arena to enter into a properly drawn up prenup," Stewart said.
One need look no further than the very ugly -- and public -- split between William's parents, Princess Diana and Prince Charles. The prince's former financial adviser, Geoffrey Bignell, told Britain's Sunday Telegraph newspaper in 2004 that Diana "took him to the cleaners," and claimed that Charles handed over his entire personal fortune -- widely reported to be more than 17 million pounds ($27 million today) -- when their marriage ended after 15 years in 1996.
But it is by no means certain an ex-wife will clean up. Following her 1996 divorce from Prince Andrew after 10 years of marriage, Sarah Ferguson complained that her reported 800,000-pound ($1.3 million today) settlement was meager. Years later, she is believed to have hired Diana's attorney to negotiate a much bigger divorce settlement after dealing with crushing debt.
But even that history doesn't mean the royals will think twice: Charles is widely reported to have ignored legal advice and opted to go without a prenup when he wed his second wife, Camilla, in 2005.
While some say it's tacky to talk about divorce at such a happy time as a wedding, doing so is a necessary evil, said Matthew Brunsdon Tully, a professor of family law at the London School of Economics and practicing divorce attorney.
Divorce can be costly, time-consuming, stressful and public -- all symptoms that a prenup can help alleviate, giving a sense of security to both sides, he said.
"A prenup might be seen as anathema to the idea that the marriage vow is supposed to be for life ... but you can't ignore the statistics," said Brunsdon Tully. With divorce rates at all-time highs "it's probably prudent of people to at least consider what might happen."
So what's at stake?
William stands to gain an inheritance from the queen, whose fortune was recently estimated at around 290 million pounds ($467 million) by the Sunday Times 2010 "Rich List." The second-in-line to the British throne also got a share of his mother Diana's nearly $34 million estate -- the bulk of which came from her divorce settlement, but it is believed much of his money is tied up in trusts.
Middleton comes from a well-off family herself but any agreement would need to ensure she is looked after, keeping up her homes and her standard of living, experts said. It would most likely be generous to ensure the prenup is not challenged as unfair after a divorce.
"They would want to make sure that things are done by the book to keep it out of the public arena," said Brunsdon Tully.
A confidentiality clause also would be a must, Stewart added, noting that "the last thing this family would want" would be a scintillating interview -- akin to one given by Diana just before the divorce -- that exposes the royal family's inner workings.
"Kate is joining a family known as 'The Firm,' and every other employee of the royal household has a contract of employment which includes a fairly severe gagging clause," Stewart noted.
Other European royals have signed prenups. Sweden's Crown Princess Victoria signed a prenuptial agreement with her husband and former personal trainer Daniel Westling that says that he would only be entitled to half of the couple's private household possessions in a divorce -- not Victoria's inheritance or her income.
Despite any alleged advantages, London-based celebrity divorce lawyer Raymond Tooth isn't convinced William and Middleton will sign a contingency plan. He noted that they have known each other for a long time, saying "it's not a whirlwind recent romance" at risk of suddenly falling apart.
Besides, Tooth thinks if a deal was signed, there would be rumors by now.
"It would have leaked out if there was one," Tooth said. "Nothing is secret anymore."