Around 500 guests are expected to attend the wedding, including celebrity guests such as Victoria and David Beckham, Elton John, singers Ellie Goulding and James Blunt, as well as royal guests like the Duke and Duchess of Cambridge.
Eugenie, 28, and her fiancé Jack Brooksbank, 32, have invited 850 guests, compared to just 600 who attended Harry and Meghan's nuptials.
It's become clear that Princess Eugenie's father, Prince Andrew, has been up to something special!
Sarah Ferguson and Prince Andrew's youngest daughter will tie the knot to her longterm boyfriend Mr Brooksbank at St George's Chapel in Windsor on Friday - just five months after Harry Wednesday Meghan Markle in the same place.
Theodora is the daughter of Ms Ayda Field and Mr Robbie Williams.
The pair has chosen a London cake designer, Sophie Cabot, to create the work of art for their big day.
During their time in Australia - which will be Meghan's first visit to the country - the royal couple will focus on "youth leadership, and projects being undertaken by young people to address the social, economic, and environmental challenges of the region".
Prince George will be joined in page boy duties by Louis de Givenchy, the six-year-old son of Eugenie and Jack's friends Zoe and Olivier De Givenchy.
Princess Beatrice will be her sister's maid of honour.
Queen Elizabeth's youngest grandchildren, Lady Louise Mountbatten-Windsor, 14, and Viscount Severn, 10, will serve as "special attendants".
Jack proposed to Eugenie, whose mum is Sarah, the Duchess of York, with a padparadscha sapphire ring surrounded by diamonds.