The joint outing -- the first with all five family members since the Trooping the Colour ceremony in June -- saw the family put on a united front amid Kate's ongoing cancer battle, which she shared publicly in March. In a video message discussing her diagnosis, the 42-year-old royal gave insight into how her kids were impacted by her health journey.

"It has taken us time to explain everything to George, Charlotte and Louis in a way that is appropriate for them," Kate said in the clip, "and to reassure them that I am going to be ok."