Royal Wedding Rehearsal: Prince William and Kate Middleton's Final Practice

VIDEO: The city is electrified by a secret rehearsal with the bride and groom.
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Kate Middleton, best man Prince Harry and the bridesmaids gathered at Westminster Abbey this morning for one last rehearsal before Friday's royal wedding at which her brother, James, will deliver the only reading.

Middleton and Prince William snuck into the abbey Wednesday night through a side door for an earlier run-through.

Buckingham Palace also released the official program this morning. The 27-page program includes the full order of service, a personal message of thanks from the bride and groom, and a new black and white photograph of the couple taken by engagement photographer and invited wedding guest Mario Testino.

It's now official that Middleton will not "obey" William but will promise to "love, honor, comfort and keep him."

They have also apparently written their own vows for the royal wedding. When Middleton, 29, was photographed leaving her family home in Bucklebury Thursday, there was a leaf of paper visible in the back seat of the car in which she was riding that included a passage from an unrecognized work.

Many of the words were obscured, but the cameras caught the sentence, "With so much love within our hearts."

It could be from a separate reading, but has aroused speculation that Middleton and William might have followed the example of many young couples and written their own wedding vows.

Meanwhile, Kate's brother, James Middleton, 23, will give the only reading at the wedding.

A global television audience of millions is expected Friday and royal fans are already camping outside the abbey. "Whether it's raining, snowing or what, this is an event that you do not want to miss," a U.S. camper said.

William, 28, spent his second to last day as a single man playing soccer in Battersea Park before screeching back, almost incognito, to the palace on his Italian motorcycle.

Middleton spent the day moving luggage. And her dad, Michael Middleton, was photographed going into the Goring hotel where Middleton and sister Pippa will sleep tonight.

"Really, privately, there's nothing particularly 'princessy' about Kate," said Duncan Larcombe, royal editor at the Sun newspaper. "She wouldn't sort of stand there and expect ladies-in-waiting to carry her bags for her. I mean, that might come when she marries into the family."

Larcombe also told ABC News that Prince Charles will be alone with his sons tonight, as Camilla is going to the Mandarin Oriental Hotel with the queen.

Also, this morning, a new photograph was released. It's another portrait of the couple by Testino, Diana's, and now William's, favorite photographer.

The picture will be in the official program, alongside a personal message from the couple that reads:

"We are both so delighted that you are able to join us in celebrating what we hope will be one of the happiest days of our lives. The affection shown to us by so many people during our engagement has been incredibly moving, and has touched us both deeply. We would like to take this opportunity to thank everyone most sincerely for their kindness."

And, finally, after the royal wedding, Larcombe said, the newlyweds will travel to America in July and are to visit Los Angeles.