Prince William misses his mother "every day".
William and Catherine in Luton
The 34-year-old royal - who is second in line to the British throne - was just 15 when his mum Princess Diana was killed in a car crash in August 1997 and he admits there's not a day that goes by when he doesn't think about her.
Speaking to a 14-year-old Ben Hines, whose mother, Alexandra, died in 2015, William told him: "I know how you feel. I miss my mother every day. It's okay to feel sad."
He added to Ben, who has three brothers: "As four boys, you have to talk a lot better, we're not good sharers. It's a classic example of lots of talking needed. Time makes it easier. I know how you feel, I still miss my mother every day and it's 20 years after she died. The important thing is to talk about it as a family, it's okay to feel sad, it's okay for you to miss her."
William was speaking as he and wife, Duchess Catherine, visited Keech Cottage Hospice Care in Luton, Bedfordshire, England.
The organisation helps adults and children with life-limiting conditions live pain and symptom free, spend time with their family and friends, and stay out of hospital.
Before leaving the family William said: "Promise me you will talk to each other."
Ben's 20-year-old brother, Thomas, said: "I promise, sir."
William and Kate's visit to the hospice was the second engagement of the day in Luton, after visiting Youthscape, a charity that specialises in young people's social, emotional and spiritual development.
Tagged in Prince William Duchess Catherine