The Princess of Wales made a rare public appearance as the emir of Qatar and his wife began a two-day state visit to the UK. The royal visitors were officially welcomed in Whitehall by King Charles before the emir inspected a guard of honour by the 1st Battalion Welsh Guards on Horse Guards Parade. The princess looked relaxed as she stepped from a chauffeur-driven car with the prince, one of only a handful of official events Kate has carried out this year. But the Queen missed the open-air greeting and a carriage ride back to Buckingham Palace, after pulling out on Monday. Camilla, 77, told guests at the state visit that her chest infection was a form of pneumonia.