The 500 guests at the Guards' Chapel in London's Wellington Barracks will include Diana's sister, Lady Sarah McCorquodale. Her brother, Earl Spencer, and Prince Charles will also attend the event - but not the Duchess of Cornwall. Camilla had originally planned to go but changed her mind - reportedly on the advice of the Queen.
Many felt it would have been inappropriate for her to attend as she had an affair with Charles while he was still married to Diana.