WATCH! A candid throwback video of the Queen, Kate and Camilla on a girls outing at Fortnums.
The secret was unveiled in the throwback video above, which shows all three royals at the luxury department store Fortnum and Mason, also known as the Queen’s grocer, on March 1, 2012.
In what was their first ever engagement together, they were each given exclusive hampers as gifts, with treats inside including dog biscuits for the Queen’s corgis and Kate’s puppy Lupo.
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."