As Gladys nodded in agreement, Prince William quipped: “Harry never got his, Gladys” – at which point the foursome dissolved into hearty laughs.
In recent weeks Prince William has shown himself to have quite the sense of humour during royal engagements.
Earlier in the month, William quipped that Kate was dressed like a “Christmas tree” during a trip to RAF Akrotiti in Cyprus.
Kate and William appeared in fine spirits as they talked eagerly with members of military personal based there.
After appearing to make a comment about the exquisitely decorated tree, William and Kate turned to pose for photographers in front of it.
“Could we see a bit more of the tree?” one person – who was presumably a photographer – asked the Prince.
“A bit more of the tree?” William quizzed. “Do you want me to move out of the photo?” he continued with fake seriousness as his wife erupted into giggles beside him.
Stepping back into the picture frame, William continued.
“My wife’s camouflaged against the tree,” he joked, appearing to make reference to Kate’s very Christmassy moss green jacket by Canadian brand Smythe.