A dozen candid and unpublished photos of Prince Charles and Lady Diana's wedding reception are the featured items at an auction in the US next month.

The photos were taken by Lord Lichfield, a relative who was the only photographer allowed to take informal photographs of the royal family and their guests when they returned to Buckingham Palace after the July 1981 wedding.

Six of the photos depict Diana in her wedding dress with members of her own family as well as the Queen, Prince of Wales, the Princess Royal, Princess Margaret and the Duke of York.

In some, Diana is holding five-year-old Clementine Hambro, her youngest bridesmaid.

The photos were left out of Charles and Diana's wedding album.

The live auction by RR Auction in the Boston area is scheduled for September 24.