Eugenie has asked Princess Beatrice, to be her Maid of Honor, the palace said, while Brooksbank has asked his brother, Thomas Brooksbank, to be his Best Man.
Prince George and Princess Charlotte will be among the pageboys and bridesmaids at the wedding of Princess Eugenie and Jack Brooksbank.
She has also asked Robbie and Ayda Williams' daughter Theodora, six, to be a bridesmaid.
Eugenie, 28, and her fiancé Jack Brooksbank, 32, have invited 850 guests, compared to just 600 who attended Harry and Meghan's nuptials.
Other bridesmaids include Maud Windsor, 5, the daughter of Eugenie's goddaughter and the daughter of Lady Frederick Windsor and Lord Frederick Windsor, and Miss Theodora Williams, the daughter Ayda Field and "X Factor" host Robbie Williams. They weren't included in Harry and Meghan's wedding so they're sure to be excited about the second royal wedding of the year.
Princess Eugenie has chosen The Duke and Duchess of Cambridge's eldest children to be part of her bridal party for Friday's royal wedding.
US stock index futures down as trading resumes
The two-year yield rose to 2.89 percent from 2.87 percent, and the 30-year yield climbed to 3.39 percent from 3.37 percent. But with the S&P 500 down for the fifth consecutive days, investors were sweating more than usual when the markets closed.
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.
Mia is the daughter of Mrs Zara Tindall and Mr Mike Tindall.
A Republic spokesperson warned "there is a strong feeling, even among monarchists, that we shouldn't be paying for Eugenie's big day ... the monarchy is stretching its public support to a breaking point".
The Earl and Countess of Wessex's children, Lady Louise Windsor and Viscount Severn will be special attendants on the day.
But the selfies are a far cry from the slick and professional photos that were relased by the Duke and Duchess of Sussex in the lead up to their Royal Wedding.