As anticipation for the royal wedding builds to ever more giddy heights, so too do the rumours, speculation and snippets of 'official' information about the big day. And while we look to previous royal weddings for clues about what to expect, each generation also brings with it new takes on tradition.
With plans for Meghan to make a speech, Prince Harry's marriage to Meghan Markle could well be the most modern royal marriage yet, so what better time to consider the 'new' wedding etiquette?
Bicester Village and Debrett's have teamed up to create the Bicester Village & Debrett's Guide to a Modern British Wedding - a comprehensive list of wedding guest fashion commandments, etiquette and royal wedding predictions. Here we share their fashion commandments and how to break them.
Thou shalt not wear black or white
While for many of us it's a wardrobe staple, black was traditionally associated with mourning - understandably not an association many people want on their wedding day. The logic behind the no-white-or-cream rule, meanwhile, is to ensure that you neither match too closely to the bride, nor look like you wish it were you standing at the altar.
And yet, all-black or white outfits can also be formal, glamorous and versatile. Today, some UK couples are even choosing a black-tie dress code, which has long been popular in the US. If you do choose to go monochrome, it's wise to check with your hosts beforehand - and to add some contrasting accessories.
Rule-bender: Cara Delevingne as bridesmaid at the weddings of her sisters Chloe and Poppy wore cream. The elder Delevingne sisters both dispensed with the no-monochrome rule when choosing bridesmaid outfits for model Cara. In fact, white or cream dresses used to be traditional for bridesmaids, and have recently come back into vogue for adult attendants.
Thou shalt not wear the same outfit twice
At a time when weddings have their own Instagram hashtag and every guest has a camera phone, we're now even more wary of recycling a wedding outfit in case our thriftiness is exposed on social media.
And yet, if you've hit on a winning look, why shouldn't it earn a repeat appearance? You're simply proving your instinct for timeless style and your understanding of what suits you. Instead, change your hairstyle and switch up the accessories to avoid accusations of outfit monogamy.
Rule-benders: The Duchess of Cambridge is well-known for her sensible approach to re-wearing the same outfit. Pictured above she is wearing the same coat to three different weddings.
A hat is a wedding essential
Visitors from the US to the royal wedding in May might be somewhat baffled by our obsession with headwear. While it's true that a hat can elevate an outfit from 'garden party' to 'elegant wedding', many women simply prefer not to wear one - whether for comfort, taste, or because they want their outfit to do the talking.
Rule-benders: Samantha Cameron (pictured above) wore a simple hair slide at the wedding of the Duke and Duchess of Cambridge, while model Karolina Kurkova showed off a fetching fascinator at the nuptials of Prince Albert of Monaco and South African swimmer Charlene Wittstock. Jemima Khan, meanwhile, goes bare-headed at her brother Ben Goldsmith's wedding: we would, too, if we had her lustrous locks.
Shoes should be practical and venue-appropriate
With summer weddings likely to be held partly outdoors, and to involve plenty of dancing, there's a tendency for guests to opt for sensible shoes. It's true that you might want to consider block heels for an outdoor wedding, but if you've found a pair of sky-high stilettos that add the requisite wow-factor to your outfit, we say go for it - just make sure your bag is big enough to conceal a pair of flats. Thoughtful hosts may even provide flip-flops for the dance floor.
Rule-bender: Daphne Guinness broke the rules at the wedding of Lady Mary Charteris and Robbie Furze. Never mind kitten, stiletto or wedge, these shoes appear to have no heels. We can only assume that sometime model Daphne Guinness is accustomed to less-than-supportive footwear - and hope that she was offered a pew soon after her arrival at the church.