There are so many rules to keep track of as a royal.
Many of which relate to fashion.
Coloured nail polish is a no-no, nude tights should be worn at all times, and wearing wedges around the Queen is very much frowned upon (she is apparently not a fan of the shoe).
But Princess Eugenie’s wedding on Friday has its very own set of royal fashion rules that guests and royal family members will be expected to strictly adhere to.
One – of course – involves millinery.
While royal protocol dictates that hats must always be worn by female members of the royal family to official events taking place before 6pm, at weddings held during the day, it is tradition for all female guests to don a hat for the occasion. And they must be worn inside the church.
Seeing as Princess Eugenie and Princess Beatrice have turned heads with their hat-game in the past – we expect to see some very striking headpieces on the day.
Other than two very stylish pieces of millinery, what else can we expect Meghan Markle and Kate Middleton to be wearing on the day?
Well, according to royal expert Camilla Tominey, they might be wearing outfits we've seen them in before.
The associate editor at the Telegraph appeared on British daytime program This Morning, with Ruth Langsford and Eamonn Holmes, earlier this week to reveal a royal wedding tradition we had never heard of before.
Apparently, it is expected that the Duchesses will wear outfits they have already worn.
According to Camilla, this is "so they do not upstage the bride".