Visiting a London hospital, Kate and William met with suicide survivor Jonny Benjamin and the man who helped save his life, Neil Laybourn.
During the meeting, William said, "Someone told me five people a day try to kill themselves. I was just blown away by the statistics."
Sitting on a sofa with Kate, Benjamin and Laybourn, he added, "For both of us, the mental health piece has got lots of aspects. It's such a big issue that we need to do something about it.
The Duke and Duchess of Cambridge meet Jonny Benjamin, to hear about his near suicide experience, and how a stranger's kindness saved his life. Jonny launched a social media campaign called #FindMike six years later, together with the charity Rethink Mental Illness, to find the man who saved him in order to offer his thanks. The campaign succeeded and Jonny was reunited with not a Mike, but Neil Laybourn. The Duke and Duchess chatted with Jonny and Neil about tackling the stigma associated with suicide, and discussed the importance of talking about mental health from a young age.
"We feel it's been raised higher up the ladder. It's suddenly bubbling just under the surface. Now we need to get up to the next level, to the surface."
Kate, who has championed efforts to beat mental health issues in children, stressed that childhood problems were the root cause of many afflictions adults face.
"We see through the work that we do with addiction, homelessness and knife crime that a lot of it stems back to childhood," said the royal mom, 34, who paired an Erdem coat (a rewear) with a swallow-print Jonathan Saunders dress.
Natalie Howarth, director of Maytree center in London, a sanctuary for attempted suicide survivors, praised the royal couple for shining a light on "the last taboo."
William and Kate, just back from a brief ski break with son Prince George, 2, and Princess Charlotte, 10 months, have increasingly been immersing themselves in the bid to tackle mental health challenges, and understanding suicide and its prevention – and the bereavement that follows – is the next step.
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As revealed by PEOPLE, the couple and Prince Harry are set to kick off a three-pronged joint campaign later this spring on mental health issues.
Suicide "is an area people don't like to discuss," Benjamin told PEOPLE this week. "Having their support will bring that message to an even wider audience."
"If people like Kate and William can address these issues, the less people will have to hide and the more open and unashamed they will be."
William has come across the issue in his work as a pilot with the East Anglian Air Ambulance. His crew has been called out to suicide cases involving young men. He has heard how the issue effects the homeless through is work with Centrepoint.
Benjamin, who is patron of Rethink Mental Illness, made a film about his experiences, The Stranger on a Bridge, which was shown to students from Dunraven School in London at Kensington Palace later on Thursday.
The couple listened, clearly moved, as one young girl hesitantly talked about her struggle with autistic spectrum disorder.
"I didn't really acknowledge the impact until I was 8 when I started to suffer from extremely bullying," she said. "I felt like I couldn't talk to anyone about it. Then a teacher came up to me – it was my 'Neil' moment – who told me I shouldn't feel embarrassed."
William and Kate nodded enthusiastically as Jonny told her, "No, no, you shouldn't."
Before they left for a private discussion with bereaved families in a nearby room after the 20 minute session, William leaned forward and spoke to the children about the importance of communication.
"If I may add anything to the expertise of what Neil and everyone else here has been talking about, that is the importance of talking to each other," he said. "I really feel that we don't listen and we don't talk enough so I hope that if anything you take away from today is to talk amongst yourselves, to share your problems and communicate and be there for each other. Thank you all for being here today and sharing."