Kate, George and Charlotte's appearance at the polo match came just a day after they joined the Queen at the Trooping the Colour parade on Saturday.
While Charlotte left us gushing over how adorable she looked even while crying, after she fell from the bench on the Buckingham Palace's balcony, one can not ignore Prince George's naughty antics.
Despite their younger brother Prince Louis and dad Prince William being nowhere in sight, Prince George and Princess Charlotte looked very happy as they played together on the grass.
And his older cousin, Savannah Phillips, seven, was even forced to put her hand over his mouth to keep him silent in hilarious footage which aired on screens all around the country.
George could be seen occupying himself with a rainbow slinky, toy guns and a kids' polo set, and rifling through Mum's handbag (naturally).
Middleton, who is still on maternity leave, looked every inch the doting mom as she chased her young children around the polo grounds, stopping to comfort Prince George who became fussy as the afternoon wore on.
One person wrote: 'This was the only disappointing thing about today's polo match photos.
Prince William and Kate Middleton's four year old son appeared to be in a mischievous mood as he stood on the balcony of Buckingham Palace with the rest of his family, including Princess Charlotte, talking the whole way through the National Anthem. Do you let your children play with them and should the royal family have let Prince George?