Prince William Gets Water Bottle Splash to the Face During London Marathon

Prince William might be royalty, but he's not above a good squirt in the face ... especially when he's on the front lines of a marathon handing out H2O.

William and Kate were at the London Marathon Sunday, being good citizens and handing out water to runners -- and this is the thanks they got.

At least the unknown practical joker had the decency to avoid the Duchess's mug.

We're guessing Will was a good sport about it. He's been known to be a happy-go-lucky future king from time to time.