Every year the Queen throws lavish reception at Buckingham Palace, known as the Diplomatic Corps reception. The 93-year-old monarch invites around 1,000 guests including ambassadors, high commissioners and government officials, as well as senior members of the royal family.
WATCH: See the royal family's tiara collection
This year's bash takes place on Wednesday 11 December and attendees must follow the strict "white tie and decorations" dress code, which means tailcoats for the gentlemen and full-length gowns for the ladies. The royals, including the Duchess of Cornwall and the Duchess of Cambridge, also wear tiaras and display their Royal Orders.
The Duchess of Cambridge at the Diplomatic reception in 2018
While you might think the reception includes a four-course meal, the set-up for the evening is actually more informal, despite the white tie dress code. One Twitter user shared the schedule from 2017 when a buffet supper was served. Guests were also split into two sittings, the first from 7 to 8pm, taking place in the State Dining, the Blue Drawing and the White Drawing rooms. The second supper, from 9 to 10pm, was served in the Picture Gallery, Green Drawing and Ball Supper rooms. During that time members of the royal family greet guests and there's also an opportunity for dancing in the Ball Supper Room after the buffet.
At last year's reception the Queen, the Duchess of Cornwall and the Duchess of Cambridge looked stunning, as they co-ordinated in white evening dresses and tiaras. Her Majesty chose a cream gown with gold floral lace detailing, teaming it with metallic pumps, a matching handbag and the Queen Mary Girls of Great Britain and Ireland tiara. Kate wore a silver-white Jenny Packham dress with sequin embellishments and Princess Diana's Lover's Knot tiara, while Camilla looked elegant in an oyster overcoat with the Greville tiara.
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