Prince William and his new wife Catherine laughed and smiled as they mingled with celebrity guests at their first official engagement in the gardens of Kensington Palace. Wearing a shimmering, dusty-pink cap-sleeve gown by Jenny Packham, the new Duchess of Cambridge and her husband were guests of honour at a lavish gala dinner hosted by financier Arpad Busson for his children\'s charity ARK on Thursday Busson welcomed the couple as they arrived to join other supporters like artists Tracey Emin and Anish Kapoor and actor Kevin Spacey, who had all paid £10,000 a head to attend the banquet in the heart of London. William, in a black dinner jacket and bow-tie, and Catherine, wearing her hair down and looking relaxed, were attending on behalf of the charitable foundation of the prince and his younger brother Harry. The dinner was held in an enormous purpose-made marquee built on the grounds of Kensington Palace, once home to William\'s mother Diana. Before dinner, the guests were entertained by a troupe of divers who leaped off boards into a specially constructed pool nearby. On June 30, William and Catherine will embark on their first overseas tour as a married couple, beginning in Canada and ending with a trip to California.