It's never ideal to turn up in the exact same ensemble as someone else but this is the type of sartorial solecism to strike dread into the heart of any guest at a wedding.
Spare a thought for the unfortunate woman who found she was wearing the same outfit as none other than the Duchess of Cambridge.
The guest, who shares mutual friends with members of the Royal family, wore the same distinctive fitted Missoni coat to a society wedding over the weekend as the Duchess.
The coat, from a 2010 collection, has already been worn by the Duchess during several public appearances, and appears to have become a staple of her wardrobe.
While most could be forgiven for fearing the inevitable comparison with the future queen, her fellow wedding guest – who has not been named – carried the occasion off with grace and good humour.
The mother of the bride diplomatically pronouncing them both “absolutely fabulous”.
Both women had been attending the wedding of Lucy Meade and Charlie Budgett in the village of Marshfield, Gloucestershire on Saturday.
Miss Meade, 29, is the sister of James Meade, one of the Duke of Cambridge’s school friends from Eton, and the best man at the Royal wedding.
The wedding was attended by numerous members of the Duke and Duchess’s close-knit circle of friends, including Prince George’s godmother Emilia Jardine-Paterson, Princess Beatrice and Prince Harry.
Prince George was not in attendance, remaining in the care of family members or his new Spanish nanny Maria Teresa Turrion Borrallo.
The Duchess has worn the coat on at least two other occasions, including at Fortnum and Mason during a visit with the Queen and Duchess of Cornwall in March 2012.
She is understood to have bought the coat during a shopping trip to the discount fashion outlet Bicester village in Oxfordshire, paying considerably less that the original retail price of £765.
The Telegraph, London
