Video report by ITV News Reporter Helen Keenan
Prince William has opened up about the death of his mother, Princess Diana, during a BBC TV documentary tackling mental health.
During the show, the Duke of Cambridge revealed he felt a "pain like no other pain" following his mother's death in a car crash in 1997.
He said: “I’ve thought about this a lot, and I’m trying to understand why I feel like I do, but I think when you are bereaved at a very young age, any time really, but particularly at a young age, I can resonate closely to that, you feel pain like no other pain.
“And you know that in your life it’s going to be very difficult to come across something that’s going to be even worse pain than that.
“But it also brings you so close to all those other people out there who have been bereaved.”
He urged people to "relax a little bit and be able to talk about our emotions because we're not robots".
While he said the "British stiff upper lip thing" had its place when times were hard, people should be encouraged to talk about their emotions.
Also appearing on the show were footballers Peter Crouch and Danny Rose, ex-players Thierry Henry and Jermaine Jenas, and England manager Gareth Southgate.
All of them shared their experiences about mental health issues.
The conversation was filmed earlier this month at the grounds of Cambridge United Football Club, which is pioneering what it means to be a mentally healthy football club.
The duke said he found the emotional side of being an East Anglian Air Ambulance pilot “very difficult”.
He said he had come from the military where feelings were put to one side, and he had seen men struggle to deal with the experience of serving in Iraq and Afghanistan once they had left the forces.
William added: “To then go in to the ambulance world, which is a much more open and actually, in some cases, very raw, emotional day-to-day stuff, where you’re dealing with families who are having the worst news they could ever possibly have on a day-to-day basis, it leaves you with a very depressing, very negative feeling, where you think death is just around the door everywhere I go.
“And that’s quite a burden to carry and feel.
“And I felt that with a few jobs that I did, where there were particular personal resonations with the families that I was dealing with.
“That raw emotion, I just thought listen, I can’t – I could feel it brewing up inside me and I could feel it was going to take its toll and be a real problem. I had to speak about it.”
In recent years William and his brother the Duke of Sussex have talked extensively about how they dealt with their mother’s death, as they promoted their Heads Together mental health campaign, which encouraged people to talk about their problems or listen to others facing issues.
A Royal Team Talk: Tackling Mental Health is part of the BBC’s wider mental health season, and is screened on BBC One on Sunday at 10.30pm.