Prince William said: "Hello Joan, do you remember we did the bingo with you? You said we weren't very good!"
Joan cheekily replied: “Yes, you did a bloody s****y job."
Though they were taken aback at first, Will and Kate took it in their stride and laughed it off.
Thankfully, 95-year-old Margaret Stocks, who was the winner of the virtual game, had a more flattering response.
"I did enjoy it. I hadn't played it before," she told them.
"Neither had we!" replied Duchess Catherine. "That's why we were so bad!"
"We enjoyed it just as much as you did," William said. "It was a new experience for us."
Prince William and Duchess Catherine also donned chic reusable face masks for their outing.
Whilst the Duke wore a blue fabric covering, Kate donned the same floral one she'd worn to a previous royal engagement - and it matched perfectly with her recycled Emelia Wickstead floral frock.
"We have to wear masks because of the virus, but it’s difficult to hear sometimes when you can't see someone’s mouth," Prince William told Joan whilst talking to her.
"Is that your assistant?" Joan asked him, pointing at his wife.
But the Duchess didn't hold back when she jumped in: "Well I am your assistant," putting a hand on her husband's shoulder. "I have been for a long time!"
Will and Kate also visited an amusement arcade on Barry Island, a tourist destination that featured heavily in the British sitcom Gavin and Stacey starring James Corden.
Their visit was to help support Britain’s tourism industry as it tries to “get back on its feet”, but the couple showed off their competitive side in a ball-throwing game.
Though the couple's three children Prince George, seven, Princess Charlotte, five, and Prince Louis, two, were absent, Prince William said of the arcade: "The children would have enjoyed that."