Before being drowned out by the ringing of bells, cooing of turtle doves and loud expostulations of the people receiving the caterers' requests for downpayments - it's important to run through a few of the most important dos and don'ts when attending a wedding.
1. Don't wear white. Just don't.
This is very basic stuff, but as we know from Victoria Beckham's appearance in ivory at Davinia Taylor's wedding and Elizabeth Hurley's attendance in a white halterneck frock at a Melbourne wedding during the Shane Warne madness a few years ago, breaches are distressingly common.
A new twist was provided last week by Emilia Wickstead who, having designed the wedding gown for the Duke of Wellington's daughter Charlotte Wellesley, pitched up at her client's nuptials wearing an almost identical dress. Same colour, same distinctive fold down, off-the-shoulder neckline.
Maybe it's the centrepiece of a new "It was so nice, I thought - I'll have one m'self!" range she's launching. Accessorise with shoes from Louboutin's new "Faux Pas" collection and add a spritz of Chanel Number Think Again.
2. Don't wear anything dramatic or absurd
Unless you're at a consciously dramatic or absurd wedding uniting two dramatic and/or absurd people of course. That's fine, though it sounds exhausting. Are you sure you want to go?But assuming you're at a nice, normal wedding full of nice, normal people, just wear something nice and normal.
Don't do a Hurley (I know, that name again, but she has such form in this area, it is impossible to leave her out) and wear a dress split so far up the front that everyone can see your spangly knickers. Don't do that. Whatever your particular damage is - neediness, insecurity, pathological narcissism - put it aside for a few hours. It's not a good look. Let the bride have her day. You can put the spangly knickers on when the dancing starts. That's fine. Scratchy. But fine.
3. Check the best man's speech
I have literally been there during a speech by a best man - a perfectly fine, upstanding citizen who had never knowingly strayed from social convention his entire life - who gaily detailed (at some length) the bedroom exploits the bride was willing to partake in, and which he felt guaranteed the couple a long and happy life together.
She burst into tears and fled. The top table went grey with horror. The groom launched himself at his friend, and the whole thing broke up in disarray.
People can go a bit mad at weddings, and this includes trusted friends.
ALWAYS CHECK THE SPEECH.
4. Mother of the bride: Don't compete with your daughter
New research may suggest you will take six days longer to choose your outfit than she did, but today really isn't about you. Or your lifetime of bitter frustration and loathing of your own husband - sitting right next to you on the front pew in THAT suit with THAT breathing.
Definitely don't tell the lambent newlyweds that you started off JUST LIKE THEM, TOO! ON A DAY JUST LIKE THIS! AND NOW LOOK AT US! before you start sobbing all over the damask. Batten it down. You've been doing it for nearly 40 years. You can do it for one more day.
5. Mother of the groom: Just smile. And say nothing
That's all you've gotta do. Just smile and say nothing. I feel your pain. I have a son. He's only five and I already hate his future wife. Just smile, and say nothing.
6. Put away your phone
Experience the day and let the wedding photographer record it.
Otherwise you're going to post a million pictures on Facebook and Instagram of yourself looking gorgeous and not notice that the bride is looking monstrous in the background of three of them. She will, though, and she will think you did it deliberately - which, let's face it, you did - and it will be the end of a beautiful friendship.
Let the circle be unbroken, and untagged, instead.
7. Don't announce anything
Not your pregnancy, your engagement, your promotion, your coming out, your decision to undertake sex-reassignment surgery - nothing. People can be happy for you another, non-focus-pulling day.
If you go into labour, keep schtum. Unless you're fully dilated by the end of the Wedding March and are crowning by the "I Do's", you can bite down on a hassock and say nothing.
People have come to see a couple pledge to end life as they know it, not witness a new one. For heaven's sake - what were you thinking? Even Hurley never went this far.