Kate Middleton and Prince William leave Westminster Hall after a Diamond Jubilee Luncheon given for The Queen on June 5, 2012 in London, England. Credit: Peter Byrne - WPA Pool/Getty

Royal deja vu!

On Tuesday, Kate Middleton and Prince William boarded a horse-drawn carriage in London for the first time since their wedding day. But unlike their royal wedding procession on April 29, 2011, the Duke and Duchess of Cambridge, 29 and 30, were joined by a third wheel: Prince Harry!

Still, even with Harry, 27, escorting them, the future King and Queen (celebrating the Diamond Jubilee of grandma Queen Elizabeth II) had millions of royal watchers reminiscing about that special day as the trio waved to crowds traveling from Westminster Hall to Buckingham Palace. And Middleton even wore her wedding dress designer -- Alexander McQueen -- for Tuesday's festivities, looking regal in a a pale pink McQueen dress, LK Bennett heels and a Jane Taylor hat.

As their carriage (an open-top state landau) went over a small pot hole, the threesome giggled. "Bit of a dip!" Harry joked.

At Buckingham Palace, the joined the Queen, 86, Prince Charles, 63, Camilla Parker-Bowles, Duchess of Cornwall, 64, Prince Harry, 27, on the balcony to greet well-wishers as a military brass band played "Land of Hope and Glory."

VIDEO: Relive all the moments from the royal wedding

Whispered Kate to William of the crowd of 1.5 million: "This is amazing!"

Unlike their last big appearance on the balcony of Buckingham Palace, William and Kate didn't do the historic "Double kiss" as they did last year.