Princess Anne looked nothing short of spectacular as she donned her military uniform to travel on horseback for the King's Birthday Parade on Saturday.
In a day which saw the Princess of Wales make a spectacular return to the spotlight in a bow-adorned white dress, Queen Camilla look divine in baby blue and the Duchess of Edinburgh turn heads in a lemon yellow ensemble, royal fans may be wondering why royalty's most stylish fashion muse, Princess Anne, wore a military uniform on the day.
As Colonel of the Blues and Royals, the 73-year-old royal wore a Full Mounted Ceremonial uniform of the Blues and Royals (Royal Horse Guards and 1st Dragoons).
She donned her full regalia to travel on horseback down the Mall, joined by Prince William, the Prince of Wales and Prince Edward, the Duke of Edinburgh.
The trio proudly wore the Collars of the Order of the Garter and Sash of the Order of the Thistle, with the Princess Royal looking smart in her bicorn hat, jodhpurs and riding boots.
Onlookers might be wondering why Anne was the only female member of the royal family to wear a uniform. Royals with military and naval connections have worn military dress on state occasions since the 19th century.
The Princess is patron of the Royal Navy and Royal Marines Charity as well as being Commodore-in-Chief for Portsmouth.
Although she hasn't actually served in the military like her brothers Prince Charles and Prince Andrew, she is an honorary Rear Admiral, and takes her role very seriously.
The Princess Royal carries out hundreds of engagements with her military patronages and affiliations every year and usually tops the hardest working royal list.