Biographer Tina Brown has revealed that the Royal Family's initial reaction to Princess Diana's death was to "do as they had always done".
The mother of Princes William and Harry died in a car accident in Paris, France, in 1997 and the Royals subsequently tried to live their lives as normal - but the youngest of the Princes, Harry, was reportedly left feeling confused by the situation.
Tina - who has made a Channel 5 documentary called 'Diana: 7 Days That Shook The Windsors' - said: "Prince Harry actually asked his father, 'Is it true that Mummy's dead?'
"The children couldn't understand why everything was as normal, except a couple of hours earlier they'd been told their mother had died."
However, a controversy erupted following Diana's death when her passing was not mentioned at Crathie Kirk church, the regular place of worship of the British Royal Family.
Speaking in the documentary, biographer Ingrid Seward said: "The first thing we saw of the boys was when they were going to church for Sunday service. And people were saying, 'How could they? These boys have just lost their mother.'"
Earlier this week, meanwhile, Prince William admitted it's taken him nearly 20 years to truly come to terms with his mother's passing.
He shared: "I am in a better place about it than I have been for a long time, where I can talk about her more openly, talk about her more honestly, and I can remember her better, and publicly talk about her better. It has taken me almost twenty years to get to that stage."
William found it especially difficult to deal with Diana's death because everything was so public.
He said: "It is a different situation for most people who lose someone they love, it can be hidden away or they can choose if they want to share their story."