Princess Mary unveiled the new National Centre for Grief in Denmark and opened up about the death of her mother.
The royal mother of four lost her own mum, Henrietta Donaldson (née Clark Horne), from a heart condition when she was just 26 back in 1997.
She paid tribute to her mum at the Danish Grief Centre's Memorial Tree, where you can hang a heart-shaped message to a lost loved one on the branches.
"I was 26. It happened too early," Mary shared in an interview with Australian Women's Weekly in 2016.
Mary went on the explain that her mother's untimely death made her a stronger person for her kids.
"It's so hard to see when it is so close and so personal," she explained.
"But as you get older, you learn to appreciate the time you had together as a gift. And that's something you wouldn't have otherwise."
"It makes a strong person," she continued.
In the past, Princess Mary has shared various admissions about her pain and grief over the loss of her mother.
"I felt alone in my pain," Princess Mary previously revealed to a Danish TV and radio station in an interview.
"As if nobody understood what I was going through and I had come to a standstill while the whole world around me kept moving forwards."
"I would have liked to have spent more time with her," she said.