It goes without saying that the upcoming funeral for the Duke of Edinburgh is going to be a monumental event for both the nation and royal family. With preparations fully underway, there are some things we know already about the service and what to expect.
It is likely that Princess Anne - Prince Philip's only daughter - may be wearing a very different outfit to the rest of the royal ladies in attendance.
MORE: Princess Anne's close bond with her late father Prince Philip
As per tradition, the 70-year-old may don her military uniform. And because royals have worn military dress at state occasions since the 19th century, we can expect this is what the mother-of-two will do.
WATCH:Princess Anne the Grandma
Although she hasn't actually served in the military like her brothers Prince Charles and Prince Andrew, she is an honorary Rear Admiral.
MORE: Princess Anne and family comfort Queen at Windsor Castle after sad death of Prince Philip
READ: Princess Anne reveals 'life will be completely different' without father Prince Philip
Princess Anne at the Queen Mother's funeral in 2002
According to The Slate, royals who don't hold a military rank wear standard mourning clothes at state funerals. An example of this is Prince Edward, who briefly served in the military and doesn't have an honorary rank. The father-of-two wore a long black morning coat to his grandmother, the Queen Mother's funeral in 2002.
Princess Anne with Prince Edward in 2002 at the Queen Mother's funeral
As expected, at her funeral over 19 years ago, many of the royals wore full military uniforms. Prince Charles wore the dress uniform of a Rear Admiral, Prince Andrew the uniform of a Royal Naval Commander, and of course Anne the trousers of a Rear Admiral. This was slightly different and unique at the time - royal women don't tend to wear trousers a great deal, particularly at important events.
Many would say her wearing trousers was actually a feminist gesture, seeing as in 2002, she was the first royal woman to wear military attire in public since Queen Elizabeth I in 1588.
READ: 10 sweet photos that show Prince Charles and Princess Anne's close sibling bond
The Queen, the Duchess of Cornwall, the Duchess of Cambridge, the Countess of Wessex, Princess Beatrice and Eugenie and all other royal women in attendance will be wearing black dresses, tights and other forms of mourning attire.
Make sure you never miss a ROYAL story! Sign up to our newsletter to get all of our celebrity, royal and lifestyle news delivered directly to your inbox.