The royal wife couldn't resist!
William, Kate and Harry attend a†Heads Together briefing

His sister-in-law, Pippa Middleton, triumphantly ran a marathon in Kenya — and now Prince William says he’d like to do the same.

“I chatted to Prince William, and he has promised that he will run a marathon in Kenya sometime,” Good Morning Britain‘s Sean Fletcher told reporters on Tuesday at an event featuring William, Princess Kate and Prince Harry to highlight their mental health charity Heads Together.

But Kate greeted her husband’s goal with a seriously raised eyebrow.

“Then I spoke to Kate and she said, ‘I’ll believe it when I see it,’ ” said Fletcher, who is planning to run in this year’s London Marathon on behalf of the charity Young Minds. Fletcher’s 13-year-old son was recently diagnosed with Obsessive-Compulsive Disorder (OCD).

“This is all very new to me — I’m learning very fast because of my son’s situation,” Fletcher added. “William’s understanding was incredible, but also his sympathy and
empathy with me.

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“He asked me lots of questions. I’ve never met him before, but he’s such a warm man. Like two dads talking together.”

Another U.K. news TV personality, Sian Williams, also attended Tuesday’s event and plans to run the marathon after recovering from breast cancer and writing a book on mental health.

“The amount of passion the royals have for this cause is really impressive,” she said. “They have researched it, they have personal experience because of the jobs they do — William taking about his role in air ambulance and Harry and his role in the military.