Back in January Kate revealed how Louis was a "fast crawler."
And by March she spilled, "Louis just wants to pull himself up all the time. He has got these little walkers and is bombing around in them."
Come May, Kate said her lookalike is "keeping us on our toes."
While meeting with World War II veterans at an exhibition marks the 75th anniversary of the D-Day landings, Kate told the women, "I turned around the other day and he was at the top of the slide — I had no idea!"
It sounds like Kate and Wills have another royal rascal on their hands!