The Only Rule Kate Middleton *Must* Follow at Meghan and Harry’s Wedding
Anwar Hussein / Getty Images

Now that the royal engagement of Meghan Markle and Prince Harry has been announced, let the ceremony speculation begin!

While we know the venue (St. George’s Chapel on the grounds of Windsor Castle, about an hour outside London), many burning questions still smolder: Who will be the bridesmaids? Who’s on the guest list? And don’t get us started on the dress.

But one fashion moment has already been set...because it’s mandatory. Like all royal women, the Duchess of Cambridge must wear a hat to all official occasions. Since Kate basically rocks every style well, from feathery fascinators to cute felt pillboxes, we can’t wait to see what she comes up with for the ceremony. (Fingers crossed that the spring arrival of the newest royal family member doesn’t keep Mum at home with baby!)

RELATED: 17 of Kate Middleton's Absolute Best Maternity Looks

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