Kate and Camilla laugh and joke together at the engagement - showing the deep friendship between the royals.
The royal ladies wore varying shades of blue for the visit – the Queen in a pastel shade outfit, Kate in a steel-blue dress and Camilla in navy.
On the UK's Channel 5 documentary ‘Inside Fortnum and Mason: The Queen’s Grocer’, the Queen’s former press secretary Dickie Arbiter commented on the momentous event.
He said: “There had the Queen, a future queen in the Duchess of Cambridge and another future queen – a queen consort – in the Duchess of Cornwall.
“So I think it was a very special occasion for Fortnums and I think a very special occasion for the Queen too in her Diamond Jubilee year."