Prince Harry told a double-amputee who is planning to row across the Atlantic for the second time that he is "an absolute lunatic".
Former solider Harry was speaking at a reception for the Endeavour Fund, a project led by his and the Duke and Duchess of Cambridge's Royal Foundation, where he stepped up the drive to help wounded service personnel through sport and adventure.
Drinking a beer after his speech, in which he paid tribute to the service personnel who "refuse to be beaten or defined by their injuries," he told Cayle Royce, 29, from Dartmouth in Devon, that he was mad to be rowing across the ocean again.
Trooper Royce, who lost both his legs in Afghanistan in 2012 and subsequently spent 48 days in a coma, is part of the first all-amputee team to row across the Atlantic, but did complete the row for the first time just 18 months after his injury.
He said: "I met Harry when I completed the row for the first time and he recognised me and told me I was an absolute lunatic for doing it again.
"You consider a lot more when you lose limbs. Having these rows to aim for really pushed me to work hard and it's only through the Endeavour Fund and seeing guys constantly generate interest in people like us that it's possible."
Joining Trooper Royce in the boat is Former Irish Guardsman Paddy Gallagher, who said: "Having this injury has inspired me to do the normal things around the house again. If I can get through this, then I get milk from the shop.
"The teamwork helps you feel normal again, and that's something we are used to in the military - a tight-knit team."
In his speech, Prince Harry spoke of how he was hoping those in need would rediscover their sense of purpose through sport.
He said: "For some people, the struggle to move beyond injury or past experience continues. They suffer in silence, unwilling or unaware of which way to turn for help; for whatever reason they have become 'the hard to reach'. No longer accessible through the traditional networks, as they have gone to ground, believing that the right help isn't out there for them, or it's all just too confusing and complicated.
"In this next phase of the Endeavour Fund, we will be asking those who have taken part in previous endeavours to take a leading role in future challenges as project managers but more significantly to act as peer mentors, forming a support network for those veterans who have not found the impulse to come forward.
"Those who have spent time in the military are proud to acknowledge that they are defined by that service. To describe yourself as a soldier, sailor or airman means something. But when that is taken away through injury or illness, sometimes that definition of self and all that goes with it can become a negative, anchoring you to the past."