She has lived most of her life outside the media spotlight and keeps a low profile compared to cousins Prince William and Prince Harry and their glamorous wives.
Eugenie was diagnosed with scoliosis when she was 12 years old and received treatment at the Royal National Orthopaedic Hospital, undergoing a successful operation to straighten her spine.
The 28-year-old bride is ninth in line for the British throne.
More recently, Kate was seen at the wedding of Robert Suggs and Sophie Carter, her best friend, wearing a Catherine Walker coat and lace dress she first wore when she visited Berlin in 2017. The singer Andrea Bocelli will perform two songs.
Not that anyone appears to have told the bride and groom. Louis de Givenchy will also be a page boy alongside George.
Guests include James Blunt, Kate Moss, Holly Valance, Naomi Campbell, Chelsea Davy, Ricky Martin, Demi Moore, Ellie Goulding, Robbie Williams, Cara Delevingne and Liv Tyler among others.
Jack works as a drinks executive for Casamigos tequila, which was founded by Clooney and Crawford's husband Rande Gerber.
In May this year, Prince Harry and Meghan Markle Wednesday in St. George's Chapel, and people flocked to Windsor to be a part of the worldwide celebrations.
About 38,000 people signed a petition, organised by campaign group Republic, against taxpayers' money being spent on the occasion.
After the service, the couple will embark on an open-top carriage tour of Windsor, although shorter than the one Harry and Meghan, now the Duke and Duchess of Sussex, took when thousands lined the streets of the town.
Eugenie and Jack Brooksbank are to marry Friday at St. George's Chapel, which is part of the castle complex.
The ceremony will take place at the castle's 15th Century St George's Chapel with the Dean of Windsor David Conner officiating.
Windsor looks set to escape the worst of Storm Callum, but the conditions could be blowy on the dry and cloudy day.
In an interview with British Vogue earlier this year, Eugenie said she is "anti-plastic" and aims for the wedding to be plastic-free.
Erdem is the favourite to have designed Eugenie's wedding dress, with other suggestions including Suzannah and Stella McCartney. The queen will then host a reception at the castle.