Charles, Prince of Wales, and Princess Diana, wave to the crowd from a coach as they pass through Fleet Street after their wedding at St Paul's Cathedral, July 29, 1981. A collection of intimate photos featuring Prince Charles and Princess Diana's wedding reception have gone up for auction. Getty Images

A collection of candid photographs featuring the 1981 royal wedding of Charles, Prince of Wales, and Diana, Princess of Wales, have gone up for auction, the Guardian reported. The collection features 12 behind-the-scenes photos of the newlyweds and other members of the royal family.

There are seven black-and-white and five color photographs in the collection, which originated from an assistant to the English photographer Patrick Lichfield, according to auctioneers. The photos are from the wedding reception held at Buckingham Palace after Charles and Diana’s famous ceremony at St. Paul’s Cathedral.

Members of the wedding party, including Queen Elizabeth II, Prince Charles, Princess Anne, Princess Margaret and Prince Andrew, are shown in some of the photos, which capture some intimate moments, such as the queen standing in front of television images showing the thousands of people who had gathered outside the palace for the wedding, the Daily Mail reported. Another photograph depicts Princess Diana’s wedding dress being arranged in the Throne Room for official photographs.

A detailed letter of provenance identifying the subjects in the photos and other specifics accompanies the photograph collection. The Remarkable Rarities live auction is scheduled for Sept. 24 in Boston.

“These never-before-seen photographs capture the candid and unrehearsed moments of the fairy-tale wedding,” said auction spokesman Bobby Livingston, the Guardian reported.

Prince Charles and Princess Diana wed July 29, 1981, when she was 20 years old and he was 32. Diana was the first British citizen to marry an heir to the British throne in 300 years. The congregation at the royal wedding included 3,500 people, and 2 million spectators lined the streets to watch the procession while 750 million people worldwide watched the ceremony on TV. Many people have deemed Prince Charles and Princess Diana’s wedding to be the “wedding of the century.”