Prince William and Kate Middleton stand on the steps of City Hall during a visit to Belfast on March 8, 2011 in Belfast, Northern Ireland © Indigo-Getty Images

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What's the difference between this week's wedding of Prince William and Kate Middleton and everyone else's? Logistics and money.

The affair -- no, make that spectacle -- is rumored to cost as much as 80 million pounds, according to reports in the U.K. press which couldn't be verified. Security alone it is slated at 20 million pounds.

No matter how you measure it, the total costs are likely to dwarf the 4 million to 30 million pounds it reportedly cost to throw the 1981 wedding of William's parents, Prince Charles and Diana Spencer.

American weddings typically cost about $27,000, according to the latest survey from TheKnot.com and WeddingChannel.com. That includes flowers, photography, music and party favors, and on these particular details there is little information available about the royal wedding. In all likelihood, the royal family will spend at least 10 times what the average American pays for such items (see chart below).

However, there are many items the family won't have to pay for at all -- such as renting a reception venue (since Buckingham Palace is at their disposal), or hiring a caterer (since the palace already has a full-time catering and event staff). As A-list celebrities, the royals also may get some nice discounts from wedding vendors.

A once-in-a-generation event

Just as with the wedding of Charles and Diana, the nuptials of William and Kate will be the wedding against which all other weddings for the next two decades will be judged. There is intense media interest in every detail, from the wedding dress to the cakes (there are two) to the brand of hosiery that Middleton will wear. A spokeswoman for Buckingham Palace declined to comment for this article. There is, however, an official wedding site with lots of details and plenty of video and photos to allow the public to share in the preparations.

Of course, the wedding reception will be a monumental undertaking. There are two parties -- a breakfast reception for 600 hosted by the queen and a dinner reception for about 300 hosted by Prince Charles at Buckingham Palace. Many celebrities are expected to be in attendance, as well as some heads of state -- although not President Barack Obama, who wasn't invited because the wedding is not technically a state occasion. Not even the tiniest detail will be left to chance.

"Everything has to work like cogs in a wheel," says Linnyette Richardson-Hall, a high-end wedding planner who is a spokeswoman for the National Association of Catering Executives and a panelist on the Style Network's "Whose Wedding Is This Anyway?" "This is a time when perfection is needed."

The couple's families are footing the bill, a smart public relations move in cash-strapped Britain. Though Middleton's family is wealthy, the event seems to be mostly bankrolled by the royals. Getting the best of everything will not come cheap, but it is likely that some of the vendors associated with the wedding are rendering their services for discounted rates or for free because of the enormous publicity they will receive. That's common practice in the U.S. for celebrity weddings and high-profile events like the Oscars.