Prince William has admitted that he's still in shock over his mother Princess Diana's death nearly twenty years ago.
The 34-year-old royal spoke about his grief in a new BBC documentary Mind Over Marathon, which focuses on 10 runners taking part in the London race, and their individual struggles with mental health issues.
"The shock is the biggest thing," the Duke of Cambridge tells one bereft marathon runner who is attempting to come to terms with the loss of her husband to suicide, five days after the death of their one-year-old son (via The Mirror).
"When your mom passed away you were a bit older than my children. I worry about them growing up. They'll be OK won't they?" the woman asks William.
He replied: "They'll be absolutely fine. With a mom like you they'll be absolutely fine. Like you said, the shock is the biggest thing.
"I have my reasons for getting involved with mental health with what happened with my mom when I was younger I still feel, 20 years later about my mother, I still have shock within me.
"People say shock can't last that long, but it does. You never get over it. It's such an unbelievably big moment in your life that it never leaves you, you just learn to deal with it.
"You'll provide the blanket of security and understanding that they'll need. You doing this is a hugely positive step."
William, along with Kate Middleton and Prince Harry have been actively campaigning for Heads Together—a charity aiming to encourage people to speak out about their mental health issues and end the stigma attached to it.
It's the charity of the year for this month's 2017 Virgin London Marathon.
"We need to make mental health normal. Working with the air ambulance at the moment I've seen a lot of sad situations involving suicide and self-harm," he says later on in the documentary.
"It's a tragedy we're not talking about it. The more we can get people talking about mental health the better as the silence is killing people."
The Duke was attending a screening of the documentary yesterday, and told the audience: "I'm speechless actually. I'm quite emotional. So I am just going to take a minute to calm myself down."
"As you can see, you know, I have my own reasons for being involved in mental health—what happened to me with my mother when I was younger—but equally the charitable work I do at the moment and the areas that I'm involved in, it all comes back to mental health."
This article originally appeared on Cosmopolitan.com/uk. Minor edits have been made by the Cosmo.ph editors.