William and Harry will each remember Diana with their own wives and children this year. Photo / Getty Images
The Duke of Cambridge and Duke of Sussex will mark the 25th anniversary of the death of their mother privately and separately, having agreed to draw a line under their public commemorations.
The brothers will each remember Diana, Princess of Wales, with their own wives and children, none of whom were able to meet her.
At the 20th anniversary of her death, they undertook major public commemorations in her name including creating a memorial garden at Kensington Palace, taking part in a documentary, loaning belongings to an official exhibition, and meeting wellwishers at the gates of their home.
They also commissioned a statue of her, which was unveiled last summer in a joint photocall despite their by-then strained personal relationship.
The Telegraph understands both Dukes have made it clear that the 20th anniversary would be the last milestone anniversary they would mark in public for the foreseeable future.
Having shared their memories of their mother and paid tribute to her legacy in person and on television, they will now continue to grieve privately on the anniversary each year.
The Duke and Duchess of Cambridge and their three children will have returned from their summer visit to the Queen at Balmoral, and be setting up their new lives at Adelaide Cottage in Windsor ready to start the new school year a week later.
The Duke and Duchess of Sussex, and their children Archie and Lilibet Mountbatten-Windsor will be at their house in Montecito, California.
The couple will fly to the UK on the week beginning September 5, when they stay at Frogmore Cottage just a short walk from the Cambridges but are not expected to spend time with them.
Prince Harry this week expressed his intention to spend August 31 privately, saying in a speech at a charity dinner: "I want it to be a day filled with memories of her incredible work and love for the way she did it.
"I want it to be a day to share the spirit of my mum with my family, with my children, who I wish could have met her. Every day, I hope to do her proud."
A source said the day was still a painful one for the late Princess's sons.
Friends of each brother separately emphasised that they would still mark it in their own ways, talking about "granny" with their young children.
Wellwishers are still expected to gather at Kensington Palace to lay flowers in Diana's memory.
Young, digital-savvy admirers will also acknowledge the anniversary online, with a new generation of Diana fans sharing videos to millions of views on platforms including TikTok.
Prince William and Prince Harry were just 15 and 12 when their mother was killed in a car crash in a Paris underpass in the early hours of August 31, 1997.
In 2017, at the 20th anniversary of the tragedy, they chose to speak extensively about her in an effort to focus public attention on her charity work rather than the circumstances of her death.
At the time, it was seen as the brothers setting out their definitive wishes about how she would be remembered.
A spokesman said then: "They wanted to feel that their mother's legacy will be celebrated in a positive way.
"The Duke of Cambridge and Prince Harry very much want to show their gratitude to the public for their continued celebration of their mother's memory."
Since then, both brothers have spoken of the Princess in the context of charity speeches and interviews.
On the 23rd anniversary, before Covid lockdown, Harry planted her favourite flowers forget-me-notes at a pre-school in Los Angeles during one of his first "engagements" of post-royal life.
A spokesman for Kensington Palace and spokeswoman for the Sussexes separately confirmed that this year's anniversary on Wednesday would be spent privately.