Queen Elizabeth II arrives along the Mall waving to the crowd as they make their way into Buckingham Palace on Friday 29 April 2011 in London, England. The couple, Princess Catherine and Prince William became engaged in October 2010 in Kenya, East Africa, during a 10-day trip to the Lewa Wildlife Conservancy to celebrate William's passing his RAF helicopter search and rescue course. London, UK - 29/04/2011