There were gasps across the world when the new Duchess of Cambridge stepped out in her wedding gown at Westminster Abbey last month.
But another princess across Europe was more stunned than most as Prince William's bride walked down the aisle in her couture gown by Sarah Burton for Alexander McQueen.
Isabella Orsini, who is the goddaughter of Italian prime minister Silvio Berlusconi, married Belgian Prince Edouard de Ligne two years ago in a startlingly similar dress.
Similarities: Italian-born Isabella Orsini (left) was stunned to notice the likeness between her own gown, from her wedding two years ago, and the Sarah Burton dress worn by the Duchess of Cambridge last month
Although hers was made for her by Belgian designer Gerald Watelet, it bore many similar hallmarks, from the lace applique bodice and sleeves to its full skirt and dramatic train.
The similarities are heightened by the fact that both women are slim, very pretty brunettes, and though the hairstyle differed, they both wore veils with diamond tiaras.
The likeness is so striking that newspapers and magazines across Germany, Belgium, France and Italy branded Catherine's dress a copy, with headlines reading 'Copy-Kate' and 'Copycat Kate'.
Both women are slim, very pretty brunettes, who married into European royalty
Ms Orsini, 36, who is an actress, makes no such claim, though she does agree that comparisons between the two sets of wedding pictures are uncanny.
She told Italian magazine Novella 2000: 'As soon as the Duchess of Cambridge went out to go to church, I thought her dress was a copy of mine.
'It means Kate Middleton has good taste.'
Making an entrance: Like Catherine, Ms Orsini had a long train on her gown by Belgian designer Gerald Watelet
Fashion statement: Catherine's dress had a full skirt and dramatic train to match the Westminster Abbey venue
Style inspiration? Grace Kelly, who became Princess Grace of Monaco when she married Ranier III in 1956
The style, it appears, is a popular one for those marrying into European royalty.
Both the Duchess and Ms Orsini's dress mirror the wedding gown of Grace Kelly, who became Princess Grace of Monaco when she married Ranier III, Prince of Monaco, in 1956.
She also had a lace bodice, on a high-waisted, full-skirted gown, which she wore with a sheer veil and diamond tiara.
Miranda Eason, editor of You & Your Wedding magazine, made the same observation.
She told the Daily Express: 'The reason they are similar is they both referenced Grace Kelly’s iconic wedding dress.'
But she added, there were plenty of differences between the Duchess and Ms Orsini's gowns.
'It’s a similar neckline and there are other similarities but the skirt, for example, is different,' she said.
Indeed Kate's vintage headwear was from an era that preceded Princess Grace's marriage - the 1936 diamond 'Halo' tiara by Cartier was her 'something borrowed' fro the wedding, on loan from the Queen.
Britain's newest Princess also personalised her look by wearing her hair in a demi-chignon, a style chosen in order that William recognise her as she walked down the aisle.
And of course, while Britain's Royal Wedding was witnessed by a congregation of thousands, and followed by two billion around the world while Ms Orsini's own wedding day was a much smaller affair.
Just several hundred watched her marry her own prince in Antoing, Belgium, whose family can trace its roots back to the 11th century.
The couple became parents last year to a daughter, Althea.
