The 'warning' Diana left William and Harry before tragic death

Despite it being 28 years since Princess Diana's tragic death, it seems the she is still imparting wisdom on her children, Prince William and Prince Harry.

Patrick Jephson, Diana's former private secretary, told People the Princess of Wales "left them many good examples to follow and also a few important warnings to heed".

"Public affection and the rich rewards of royalty must be earned with self-sacrifice and service," Jephson said.

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"I'm sure they are grateful that every day she can still guide, comfort and inspire them along the difficult path they were born to follow."

William and Harry were 15 and 12 respectively, when their mother was killed in a car crash in Paris on August 31, 1997, aged just 36.

Though they were close in childhood, a rift has come between them caused by their differing life choices, with experts fearing there is no way back for the brothers.

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Author Edward White, who has written the book Dianaworld: An Obsession, said there is an added layer to their sibling rivalry.

"It's like there's a church schism going on, both of them seem to think that they are upholding Diana's true legacy," White told 9honey from his home in Kent.

The brothers are carefully choosing their royal work to align with things that are "truly important about her."

Most recently, Prince Harry walked in the footsteps of his mother through a former landmine in Angola, while Prince William is forging ahead in his landmark program to end homelessness across the UK.

"The point of my book is that people – from different communities and backgrounds – are seeing in Diana what they want to see and the same seems to be true even of her children," White said.

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