William, 33, was confronted by male suicide when flying missions for his air ambulance charity: In some of those early missions with East Anglian Air Ambulance last summer, William transported medical crews to the aid of men whose despair led them to take their own lives.
It's also understood that William, who has been aware of the depression and other problems facing young people through his work with homelessness charity Centrepoint, has also been alarmed by the suicides of young gay men.
Later this spring, the prince will highlight male suicide and the troubles facing young men as he joins with Kate, 34, and Harry, 31, in their efforts to improve mental health.
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While William has taken on ongoing role in tackling the problems faced by men, Kate has been highlighting vulnerable children and Harry is concentrating on what he calls the "invisible" injuries suffered by servicemen and women.
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William and Kate previously teamed up for a visit to the charity Mind last year.
A Kensington Palace spokesman tells PEOPLE, "The Duke and Duchess of Cambridge and Prince Harry are continuing to work with mental health experts and charities to help raise awareness of a variety of issues within the sector."
William's efforts, which were first reported by The Times, emerged after days of controversy over the number of shifts that he carries out with the air ambulance that he dovetails with royal duties.
He has been at three of those duties so far this year – the latest on Friday night at the Welsh rugby stadium.