It's often said that money can't buy you love ... but it certainly can buy one lavish wedding.

Just ask celebrities. Ever since Lady Diana Spencer and Prince Charles were married on July 29, 1981, the bar has been set pretty high for vow-exchanging celebs, and they continue to keep raising that bar with every "I do."

Take Chelsea Clinton's July 2010 wedding for instance. Rumors swirled that the wedding that had Washington politicos all abuzz cost anywhere from $3 million to $5 million.

Chelsea, now 30, was only a toddler when Di and Charles got married at London's St. Paul's Cathedral before a TV audience of 750 million. In an over-the-top fairytale wedding fit for, well, royalty, the most extravagant item was Lady Di's dress, which featured a 25-foot long train and 10,000 hand-sewn pearls and sequins and came to be dubbed the most signature wedding dress of all time.

But even that royal wedding -- and perhaps even Chelsea's -- pales when compared to our choices for the five most extravagant celebrity weddings of all time.

Over-The-Top Celeb Wedding No. 5: TomKat Ties The Knot >>