Prince William wants to run a marathon, Kate Middleton 'will believe it when she sees it'

Kate Middleton is Prince William's number one support system, but when it comes to the Prince running a marathon, she needs a little proof before cheering for him on the sideline.

During an outing with William and Prince Harry in support of their Heads Together organization at the Institute of Contemporary Art in London, on Tuesday, William shared with one of the attendees his promise to run a marathon in Kenya. "I chatted to Prince William, and he has promised that he will run a marathon in Kenya sometime," Good Morning Britain's Sean Fletcher shared.

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When it comes to Prince William running a marathon, Kate says she will believe it when she sees it Photo: Karwai Tang/WireImage

When Sean, who will participate in the London Marathon in support of his son's diagnosis with Obsessive-Compulsive Disorder (OCD), told the 35-year-old Duchess about her husband's news, Prince George and Princess Charlotte's mom offered up the hilarious response, "I’ll believe it when I see it."

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“This is all very new to me — I’m learning very fast because of my son’s situation,” Sean continued. “William’s understanding was incredible, but also his sympathy and
empathy with me. He asked me lots of questions. I’ve never met him before, but he’s such a warm man. Like two dads talking together.”

Kate and Harry spoke to guests during their outing at the Institute of Contemporary Art Photo: Twitter/@kensingtonroyal

William, Kate and Harry's organization Heads Together has been chosen as the Charity of the Year for the marathon. During her speech, Kate, who wore a floral dress by Erdem, stressed the importance of speaking about mental health. "What Heads Together is proposing is that in the weeks leading up to the marathon, our campaign will showcase people from all walks of life, talking about the life-changing conversations that have helped them with their mental health challenges," Kate said. "We hope that these real-life examples will serve as encouragement to others to do the same."

William, 34, Kate and Harry, 32, will be cheering on the runners including UK TV personality Sian Williams, who will be running the marathon in April after recovering from breast cancer and writing a book on mental health.

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Kate wore a floral number by Erdem Photo: Karwai Tang/WireImage

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While she agrees that it would be nice to see the trio on the course and running for the cause, she understands why that isn't possible. "You get a very keen sense it's something they have been aware of for a very long time and they feel as though they can help get the talking going," she said. "Obviously they can't run themselves because there would be 26 miles of royal protection officers so I think having us run it for them as part of a team, they'll be there to cheer us on."

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