By Stephanie Linning For Mailonline
Published: 13:46 GMT, 3 March 2020 | Updated: 20:49 GMT, 3 March 2020
Princess Diana was distracted by Camilla Parker-Bowles after catching sight of her on her wedding day, a royal biographer claimed.
Speaking on this week's episode of CNN documentary series The Windsors, royal biographer Sally Bedell Smith tells how Diana spotted Charles's ex-girlfriend as she walked down the aisle at London's St Paul's Cathedral on 29 July 1981.
The American author and historian, who has penned biographies on Diana, Charles and the Queen, explains that Diana found herself competing with Camilla, even on that most 'magical' of days.
Royal biographer Sally Bedell Smith tells how Diana spotted Charles's ex-girlfriend Camilla (circled) as she walked down the aisle at London's St Paul's Cathedral on 29 July 1981
'As Diana walks down the aisle with her father, she sees Camilla,' Bedell Smith says in a clip shared exclusively with FEMAIL.
'There she is, on this magical day, and the one thing she is focusing on is the image of Camilla.'
The six-part CNN Original Series, which is airing in the US, tells the story of the Windsor dynasty, starting with King Edward's ascension to the throne and working towards the future of the monarchy.
This week's episode, which airs on Sunday night, is titled Love or Duty, and focuses on Prince Charles's romance with the then Camilla Shand, the loss of his