LIZ JONES: You should never have a bridesmaid younger, thinner and more beautiful than you are

It's like choosing to hold your wedding during a total eclipse of the sun. Except in this case, you are rendered utterly invisible not by the movement of the heavens but by the far-too-beautiful woman at your side whom you rashly appointed as a bridesmaid.

It's bad enough walking up the aisle watching all the heads turn just a fraction after you've passed them.

But at the altar itself there is a sudden, ominous chill in the air. An ill wind. Birds take flight, as if sensing a tsunami. You've just handed this temptress your bouquet and, feeling completely outclassed, you now hope the pollen leaves a yellow stain on her pastel-coloured gown, and the thorns draw blood.

Margot Robbie was bridesmaid to her best friend from school, Brittany Claxton, in their native Queensland, Australia

Shoehorned into halter-neck ivory silk to match her hair, Margot just looked so good

What were you thinking, allowing this Helen of Troy, this exquisite princess, to play a part in the most important day of your life?

The groom glances at you, and then at her, his gaze lingering just a fraction too long. He is wondering if it is too late to change his mind... And can you blame him, when the woman you chose is the human embodiment of every man's fantasy: bloody Barbie!

At the weekend Margot Robbie – yes, she of the impossibly elegant limbs not long ago seen wrapped, pretzel-fashion, around Leonardo DiCaprio in the Wolf of Wall Street, a woman who managed to make pink gingham look cool and has the sort of teeth that can blind a man at 20 paces – was bridesmaid to her best friend from school.

What was her name again? Oops, like the groom (possibly), I've forgotten it (I can only imagine that when asked to say the words 'I take thee...' he had to fight very hard not to do a Ross from Friends and utter the one that was really on his mind). Oh yes, Brittany Claxton, that's it! At one point she was seen wearing dark glasses, probably to stop herself being blinded by her old friend.

Never mind Barbie vs Oppenheimer at the box office, I'd have gone nuclear!

For the truth is, Margot just looked so good. Shoehorned into halter-neck ivory silk to match her hair, she moved like mercury. For the next day's Las Vegas-themed celebrations, she changed into a – yes, you guessed it! – Barbie-pink tutu. Did Brittany know in advance, or did her inward groan last the entire day?

Supermodels Bella Hadid and Kendall Jenner were bridesmaids for fashion blogger Lauren Perez . Lauren did what any right-minded woman would do and dressed them in off-the-peg dresses costing £207: the supermodel equivalent of putting them in Primark

I am now slightly worried she has invited her old friend on her honeymoon. It's a new trend, apparently, to ask friends and family to come along. The prospect of Margot in a bikini would make it very tempting indeed to drown her.

So what is the etiquette here? Should you ever choose a beautiful bridesmaid, even if, like Margot, she is happily married? Should you ever choose someone younger, thinner, and way more successful than you? Or can you legitimately leave her out on the grounds it's your day and yours alone?

I suppose to pick a beauty for this starring role could be like sending a canary down a coalmine – if the groom is paying her too much attention, you can save a huge sum in divorce lawyers further down the line. Better to find out now if he is easily swayed.

Ultimately, however, I think having your own version of Barbie as bridesmaid is to dice with your future happiness. But you need to be canny when it comes to neutralising her effect. I am reminded of the wedding of fashion blogger Lauren Perez, who had as bridesmaids the supermodels Bella Hadid and Kendall Jenner. Lauren did what any right-minded woman would do and dressed them in off-the-peg dresses costing £207: the supermodel equivalent of putting them in Primark.

Cara Delevingne, invited to Princess Eugenie 's nuptials in 2018, completely upstaged the royal bride by turning up in a top hat and tails

Overly attractive female guests can also be a fly in the ganache, so best to scrub them too: one serial offender is Kate Moss, who wore a grey shorts suit to attend the wedding of stylist Katy England in 2006, ensuring even the vicar lost focus. Cara Delevingne, invited to poor old Princess Eugenie's nuptials in 2018, completely upstaged the royal bride by turning up in a top hat and tails.

I had just one bridesmaid when I got married in 2002. Anna is my niece and doppelganger, then a gangly teenager I dressed in an Alberta Ferretti gown and Gina shoes (I wore a boring tuxedo in white). I was marrying a man 15 years my junior, so perhaps I wanted him to know what I used to look like.

I also had a maid of honour, my best friend and former PA Kerry, who rather disloyally spent the wedding eve playing pool with my future husband and the day of the wedding nipping outside with him to share roll-ups. I could almost see his brain thinking: 'This is more my kind of woman. One of the lads.'

But here's the thing: my maid of honour and I got on so well, made each other laugh so much, wasting a great deal of champagne snorting it out of our noses, that she was this close to coming on our honeymoon.

Liz Jones wore a white suit at her wedding in 2002 while her niece Anna was a vision in an Alberta Ferretti gown and Gina shoes

I felt I needed someone to talk to rather than the morose chippy lump my husband morphed into. And, as it turns out, my beautiful bridesmaid was the least of my problems. I did make one significant mistake, however, in hiring a gorgeous Brazilian wedding photographer called Leticia. She looked like Gisele Bundchen and every man at the wedding, including the groom, was salivating over her. My new husband even abandoned the top table to sit with her during the speeches.

I was so enraged that I requisitioned her room at Babington House for my nephew, banishing her to a pub down the road.

But of course the unique allure of the bridesmaid isn't just about their beauty.

The universal problem with bridesmaids, not just those who are Hollywood megastars, is that on the Big Day they are always way more relaxed than the bride, a quality most men, allergic to pressure and detail, find infinitely attractive. Bridesmaids always seem to enjoy the day with gay abandon: none of the stress, none of the worry about cost.

Whereas brides always bear an expression – or at least, I did – of barely concealed, hyper-vigilant hysteria.

Happily, it isn't just bridesmaids we should all be wary of. Grooms: beware the best man, especially if he is taller, wittier, and has a gold tooth.

I wonder if Kate Middleton spied Prince Harry, grinning from ear to ear, and thought for a fleeting second that she might have more fun with him?

As I teetered down the staircase towards the altar, mindful I was in Bottega heels and had drunk a magnum of champagne, my husband's best man (you can just see him in my wedding photo, ding dong!) whispered conspiratorially, taking my arm: 'If it all goes t*ts up, you've got my number.'

In the immortal words of Bonnie Tyler, the total eclipse of the heart really can work both ways.