The Duke of Cambridge and Prince Harry are still living with the devastating emotional impact of their mother's death.
The royal brothers chose the 20th anniversary year of the car crash that killed Diana, Princess of Wales to begin talking candidly about how they are still grieving.
The backdrop to the year has been William, Kate and Harry's mental health campaign, Heads Together, which has encouraged people to speak about their problems or be a sympathetic ear for others in need.
And it appears they have followed their own advice and talked openly about losing a parent and the psychological issues that can follow.
William was 15 years old and Harry just 12 when their mother Diana, 36, her lover Dodi Fayed, 42, and their chauffeur Henri Paul were killed when their Mercedes crashed in the Pont de l'Alma tunnel in Paris on August 31 1997.
Days later images of the young princes walking behind the horse-drawn gun carriage transporting their mother's coffin through the streets of London were etched in the public's memory.
But the Duke and Prince appear to have dealt very differently with the emotional fallout following their bereavement, with William seemingly coping better with his feelings of "anger" while younger sibling Harry admitting to receiving professional help.
In an interview with Newsweek magazine, Harry voiced his disapproval at having to walk behind Diana's funeral cortege watched by thousands with his older brother, his father the Prince of Wales, grandfather Duke of Edinburgh and his uncle Earl Spencer.
Harry said: "I don't think any child should be asked to do that, under any circumstances. I don't think it would happen today."
Diana's brother Charles, Earl Spencer, has claimed he was "lied to'' about the desire of William and Harry to walk behind their mother's coffin.
In a BBC interview he said he raised objections with royal officials before being told his nephews wanted to do it, adding he later realised this was not the case.
He described the experience as the "most horrifying half hour of my life'' but said he believed it was a "million times worse'' for Diana's sons.
Harry revealed the true extent of his problems in an interview with the Telegraph describing how he sought counselling after two years of "total chaos'' having spent nearly 20 years "not thinking'' about the death of his mother.
The Prince said he stuck his "head in the sand" and refused to think about his mother because that would not bring her back.
"And then (I) started to have a few conversations and actually all of a sudden, all of this grief that I have never processed started to come to the forefront and I was like, there is actually a lot of stuff here that I need to deal with," he said.
He sought help after his older brother said he needed to deal with his feelings.
In the long run William, who is three years older than Harry, coped better with the loss although at the time he said he felt "very angry" and found it very difficult to talk about his mother's death.
His job may have helped him deal with his emotions as for much of his working life he has been called to the aftermath of traumatic incidents as an RAF search and rescue helicopter pilot or an air ambulance flyer.
Crews are likely to have been encouraged to debrief and talk about their experiences and feelings as a way of coping with the things they have seen.
The Duke told Tony Blair's former spin doctor Alastair Campbell, in a GQ magazine interview, the closest he got to mental health issues was the "trauma I suffered when I lost my mother".
He went on to say "I still haven't necessarily dealt with that grief as well as I could have done over the years", but had talked to family, friends and those around him he could trust.
Unlike brother Harry who has admitted to seeing, as the Telegraph interviewer put it, a "shrink", William said: "...on grief, I find talking about my mother and keeping her memory alive very important.
"I find it therapeutic to talk about her, and to talk about how I feel."
