Princes William and Harry will officially mark the occasion of the death of their mother on the eve of the twenty year anniversary.
They will visit the garden at Kensington Palace, Princess Diana’s former home, which has been created in her name.
The Sunken Garden in the palace grounds was designed to honour Diana’s memory and has been planted with white flowers by gardeners who knew the Princess from her frequent visits there.
The Duke and Duchess of Cambridge and Prince Harry will meet workers there from the charities which their mother supported before she died.
It is the final engagement before the anniversary of her death on Thursday.
Neither of her sons will make any public appearances on August 31 – the day she was killed in that car crash in Paris in 1997.
William and Harry have given two interviews – one each to ITV and the BBC – so the two broadcasters could make key documentaries on the Princess of Wales.
They don’t intend to speak about her death or her legacy again.
The focus on events twenty years ago has been a painful reminder for the country of a very unhappy and unsettling period for the Royal Family.
The sudden death of Diana,and her boyfriend Dodi al-Fayed, came after many years of rumour, gossip and bitter fighting – both in public and in private.
Truths and untruths were spread via stories in the press.
The result was a Monarchy which suffered a great deal of damage to its reputation.
The Queen also took a rare misstep when she misjudged the mood of the country and stood by her decision to stay at Balmoral Castle until the day before Diana’s funeral.
Recent polls have shown the increasing publicity around Princess Diana in recent week has had a negative impact on her former husband.
Prince Charles will therefore be relieved at today’s attention to the comments from Prince Harry on how his father “did his best” and “looked out for” the two boys in those difficult moments after the car crash.
William and Harry do want to move on – and they hope that the 20th anniversary is a good moment in which to do so.
There is, however, one more way in which they plan to honour their mother.
Earlier this year, they commissioned a statue of her to be erected in the grounds of Kensington Palace.
The design of the statue - and the unveiling of it - will take place later in the year.