Prince William and Kate Middleton, who tied the knot in a royal wedding in 2011, surprised their wedding guests with an unexpected number.

Following the ceremony at Westminster Abbey, which was watched by millions of people around the world and attended by numerous celebrities, the couple hosted two private receptions to enjoy a more relaxed celebration with their loved ones.

The Prince and Princess of Wales shocked their wedding guests when the newlyweds performed the iconic dance routine from the film FatAccording to the new book by royal biographer Robert Jobson Catherine, Princess of Wales.

“Prince William and Kate had a special surprise in store for the finale of the evening,” Jobson says in the book.

“They stood in the middle of the dance floor holding hands and grinning, then suddenly the first bars of the song You are the one who I want from the musical Fat came out roaring,” wrote Jobson about People magazine.

“Then William and Catherine started dancing around, pointing at each other and singing along to the words in the style of the main characters Danny and Sandy. It brought the house down.”

Jobson also stated that 1,900 guests attended the wedding ceremony, but fewer people attended the celebrations afterwards.

A reception hosted by Queen Elizabeth II was attended by 650 guests, and one hosted by King Charles was attended by 300 guests.