Daily Mail reports that Eugenie will be joined at the altar by Robbie William's five-year-old daughter.
Both Eugenie and Princess Beatrice are said to be very close friends with the British pop star, and wife Ayda Field.
The couple's young daughter, Theodora Rose, will also be joined by Princess Charlotte.
Prince George has also been asked to be a page boy.
Princess Charlotte is already an experienced bridesmaid - having participated in two high-profile weddings already, including Pippa Middleton's wedding to James Matthews and Prince Harry and Meghan Markle's nuptials.
The bride-to-be announced her engagement to Brooksbank on January 22, after the nightclub manager proposed to her during a trip to Nicaragua.
'I was over the moon,' Eugenie told the BBC. '[It was a] complete surprise. But it was the perfect moment, we couldn't be happier.'
This article originally appeared on New Idea