Kate Middleton may be a member of the royal family, but that doesn't mean she's shy about keeping it real.
Earlier today, the Duchess of Cambridge delivered a moving speech alongside her husband Prince William and brother-in-law Prince Harry in service of their mental health organization Heads Together, and it seems as if the talk later turned to the group's athletic pursuits.
"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 at the event. However, Princess Kate seems to be somewhat skeptical of the Duke's ability to follow through and had the response that many wives would—one of disbelief. "Then I spoke to Kate and she said, 'I’ll believe it when I see it,'" said Fletcher.
VIDEO: The 10 Cheapest Things Kate Middleton Has Ever Worn
As you might recall, the Duchess's sister Pippa Middleton ran a marathon in the East African country back in July of 2015, just a week after completing a 54-mile charity bike ride. Looks like Prince William wants to see if he can keep up with his sporty sister-in-law. Only time will tell if he can do it.
Check out more of Kate Middleton and Prince William's cutest moments in our gallery.