The Duke of Cambridge is well aware of what he’s in for when daughter Princess Charlotte gets older, and he’s getting ready.

"She's going to be trouble when she gets older," Prince William told Pagan Tordengrav while visiting with patients at Aintree University Hospital on Thursday. "All fathers say that to me — watch out for the little girls."

The royal's joke comes a few months after the 2-year-old princess threw a royal fit on a tarmac in Germany. Luckily mom Duchess Kate came to the rescue and calmed her down, but the adorable photos still circulated online. Even earlier this year, the Duchess of Cambridge admitted Princess Charlotte is "the one in charge" of their household.

On the other hand, Prince William said he believes his son will a breeze as he grows up.

“George has been really easy,” he told patient Theresa Jones when asked about George starting school. “He hasn’t said, ‘Have I got to do this for the rest of my life?'”