From the engagement to the reception, royal wedding planning comes with more protocol than you can shake a tiara at (and you think your wedmin list is crazy!). So, will Harry and Meghan embrace all these formalities and pull off a totally trad day? Perhaps they'll break a few conventions… or give them a new twist. Here are some of the customs they've already ticked off during their engagement, plus the big-day etiquette they'll be thinking about - and we'll all be watching out for on 19th May!
1. The monarch must give written permission for the wedding - this applies to the first six people in line to the throne. Happily for Harry, his grandmother, the Queen, wrote a letter giving her consent to the match on 14th March (using Meghan's full name, Rachel Meghan Markle).
2. There is a formal announcement of the engagement, and an official photo call. After the announcement in November 2017, Harry and Meghan posed for pictures in the Sunken Garden at Kensington Palace (a favourite spot of Harry's mother, Princess Diana).
3. Official portraits are taken. Harry and Meghan's were shot at Frogmore House, near Windsor Castle, by fashion and celebrity photographer Alexi Lubomirski; Meghan wore a £56,000 couture gown by Ralph & Russo for the occasion.
Outfits & accessories
4. The bride's gown is white. A tradition started by Queen Victoria at her marriage to Prince Albert in 1840 - and ever since, brides everywhere have followed her sartorial cue!
5. And the groom wears military uniform. As a former soldier and current Captain General Royal Marines, Harry would be entitled to wear his military garb (like William did for his wedding) - although some experts believe that since he is no longer a serving officer, he may choose morning dress instead. Either way, we're sure he'll look dashing!
6. The bride wears a tiara. If Meghan wants to stick with this tradition, there are plenty of pieces in the royal vaults for her to choose from. But we know she won't be wearing the Cartier Halo that Kate wore, because it's due to be on display in Australia at the time of the wedding.
7. Royal wedding bands are made of Welsh gold. The Queen Mother started this trend in 1923 - and since then, royal brides from Princess Diana to Kate Middleton have followed suit, with several rings being fashioned from the same nugget.
The flowers & cake
8. The bride's bouquet contains a sprig of myrtle. Another tradition that dates back to Queen Victoria - myrtle from her garden (planted in 1845!) has been used in royal weddings ever since her eldest daughter, Princess Victoria, carried it in her bouquet. Harry and Meghan have chosen Brides favourite Philippa Craddock to create their floral arrangements, which will feature wildflowers supplied by The Royal Parks - and we can't wait to see how (or whether!) she works myrtle into the mix…
9. The bride lays her bouquet at the Grave Of The Unknown Warrior in Westminster Abbey. This custom began with the Queen Mother in 1923, who laid hers in honour of her brother, Fergus, who died in WW1. Since then, royal brides including Kate, have kept up this touching tradition.
10. Historically, royal couples choose fruitcake. But Harry and Meghan have gone their own sweet way - they've asked Claire Ptak, owner of Violet Bakery, to create a lemon and elderflower confection, covered with buttercream and decorated with fresh flowers. Delicious!