Prince William and Kate Middleton took their children, George and Charlotte, to Princess Diana's grave to mark her 56th birthday.
The two youngest royals - aged three and two - obviously never met their grandmother, who died in a Paris car crash in 1997.
The family paid a private visit to Diana's final resting place at the Spencer family estate on Saturday, to attend a service conducted by Justin Welby, the Archbishop of Canterbury, and re-dedicate Diana's grave 20 years after her death.
It is important to them that George and Charlotte are able to show their respects
A source told The Mirror that the family ceremony had been "age appropriate", adding: "It is 20 years since Princess Diana’s death and it is important to them that George and Charlotte are able to show their respects.”
Other members of Diana's family in attendance included Prince Harry, Diana's brother, Earl Spencer, and her sisters Lady Sarah McCorquodale and Baroness Fellowes.
Diana's grave is situated on an island in a lake named The Oval within the grounds of Althorp Park, her family.
William was 15 years old and Harry was just 12 when the Princess of Wales died in a Paris tunnel after a car collision.
She was only 36 years old.
In a recent interview with GQ, William, now 35, spoke of his sadness that Diana never got to meet his wife Kate or their two children.
"I would like to have had her advice," he said.
"I would love her to have met Catherine and to have seen the children grow up. It makes me sad that she won’t, that they will never know her."
"One thing I can always say about my mother is she smothered Harry and me in love. Twenty years on I still feel the love she gave us and that is testament to her massive heart and her amazing ability to be a great mother."
In a separate interview with Newsweek, Harry, now 32, spoke about the pain of having to walk behind his mother's coffin at her funeral when he was so young.
"My mother had just died, and I had to walk a long way behind her coffin, surrounded by thousands of people watching me while millions more did on television,” he said.
"I don’t think any child should be asked to do that, under any circumstances. I don’t think it would happen today.”
William and Harry have commissioned a statue of their mother to mark the 20th anniversary of her death.
It will be displayed in the grounds of her old home, Kensington Palace, where William now lives with his family, and Harry has an apartment.
Announcing the public tribute in January, they said: "It has been 20 years since our mother's death and the time is right to recognise her positive impact in the UK and around the world with a permanent statue.
"Our mother touched so many lives. We hope the statue will help all those who visit Kensington Palace to reflect on her life and her legacy."