While many members of the royal family joined the Queen and Prince Philip at the Patron's Lunch on Sunday, Prince Charles and the Duchess of Cornwall were noticeably absent. Instead the royal couple attended The Big Lunch in Brimpsfield, Gloucestershire.
Camilla is Patron of The Big Lunch, which brings friends, neighbours and communities together to celebrate Her Majesty's birthday, and thus wanted to join local residents for the occasion.
Prince Charles and the Duchess of Cornwall attended The Big Lunch in Gloucestershire
Prince Charles and Camilla sat alongside revellers at the party, where they tucked into egg sandwiches, crisps and cakes under a marquee that had been decorated with bunting and Union Jack flags.
The Duchess even bought along a cake that had been baked in the Clarence House kitchen especially for the occasion, which she proudly presented to guests. Decorated with a Union Jack and red, white and blue butterflies, it was a patriotic addition to The Big Lunch.
Camilla is Patron of The Big Lunch
Meanwhile local school children dressed up in regal costumes for a fancy dress competition, with one young boy dressed as a Corgi, while others dressed up as Kings, Queens and Beefeaters.
The Prince of Wales' absence from the Patron's Lunch was questioned by many royal fans on Twitter, as he and Camilla were the only senior royals not to join in the festivities.
The Duchess brought along a homemade cake to the party
His sons Prince William and Prince Harry had both spent half an hour mingling with the 10,000 guests who had lined the Mall, along with Princess Anne, Prince Edward and Prince Andrew.
The event, organised by the Queen's grandson Peter Phillips, was well-received by the Monarch, who thanked fans for all of their birthday wishes in a short speech. The Queen prompted cheers and laughter from the audience as she joked that she may not feel the same if she continues to hear Happy Birthday until the end of the year.
"I much appreciate the kindness of all your birthday wishes, and have been delighted and moved by the many cards and messages I have received," the Monarch told the audience. "How I will feel if people are still singing Happy Birthday to me in December, remains to be seen!"