During a visit to Child Bereavement UK in Stratford, east London, on Wednesday, Prince William leaned in to speak to a girl named Aoife, 9, to tell her they had something very important in common.
"Do you know what happened to me?" Prince William asked the young girl, who lost her father to pancreatic cancer six years ago, according to PEOPLE magazine. "You know I lost my mummy when I was very young too. I was  and my brother was 12. So we lost our mummy when we were young as well."
William and Harry's mother, Princess Diana, was killed in a tragic car accident in 1997. "Do you speak about your daddy?" Prince William asked Aoife. "It's very important to talk about it, very, very important."
More Moments That Matter videos
Watch this dad erupt with joy after learning he has a new baby boy
Watch these NICU babies, now feisty toddlers, in their inspiring calendar photo shoot
See Dylan Dreyer’s baby Calvin greet the day with a huge smile
See Hoda Kotb’s tearful reunion with Kathie Lee Gifford: ‘Where’s my other girl?’
Prince William and Catherine, Duchess of Cambridge, spent part of their time at the charity, which provides support for grieving children and their families, making "memory jars" full of tightly packed colored salts — each color meant to represent a memory about the person they lost.
The princes William and Harry have spoken more about their mother's death in recent years. Sharing their loss is having an impact on others who know that pain, Aoife's mother told reporters. "I couldn’t believe it when he started to talk about his mother. It was very emotional and I was willing myself not to start to cry. I almost did," PEOPLE's Simon Perry reported.
“I am telling my children that if they take anything away from this day, it is what he said about how important it is to talk. Kids do not forget that. Sometimes it hurts but we can remember the happy things too. It is so important to talk.”
Earlier in the day, the former Kate Middleton visited London's Anna Freud National Centre for Children and Families, which helps children and young people grappling with various mental health issues. While meeting with a group of young mothers who had undergone treatment for issues like abuse and addiction, Kate acknowledged that all mothers struggle, including herself.
"Parenting is tough. And with the history and all the things and experience you've all witnessed, to do that on top of your own anxieties, and the lack of support you also received as mothers... I find it extraordinary how you've managed actually," she told them, PEOPLE reported.
“She knew exactly what these mums were talking about — about children not sleeping and how stressful it is to try and bring up small children,” Peter Fonagy, chief executive of the Anna Freud Centre, told PEOPLE. “All the mums said how much she talked to them as just another mum.”
Kate, who has focused on mental health issues in her royal duties, is using the common experience of motherhood to relate to parents struggling with more than the usual stressors in their parenting.
“She is totally convinced that early intervention is the way to go — that mums need support and help. When you can’t sleep because of a young baby and you’re on your own, it is tough," said Fonagy.
No one knows that better than another mother, whether she wears a tiara or not.