While we may never know the contents of the joke, a lip reader has since determined that when the Queen greeted the FLOTUS on the steps of Buckingham Palace, Her Majesty said: “Nice to see you again”.
Luckily for us, it seems the lip reader had more success when it came time to deducing the exchange between US president Donald Trump and Prince Charles.
According to Express.co.uk Charles greeted Trump like a close pal:
“Are you doing well, Donald?", the prince of Wales said, before outstretching his hand for a 10-second long handshake.
According to lip reader Tina Lannin, Camilla Parker Bowles was just as friendly as her husband, telling Donald and Melania Trump: "Nice to meet you."