Tom will take up the role in St George's Chapel in support of his brother as he marries Princess Eugenie in front of a worldwide audience.
Princess Eugenie's wedding is only a few days away, but there's one key person who will be missing from the guest list: Prince Charles' wife, Camilla Parker-Bowles.
In fact, they've had plenty of practice at the roles, as they were also page boy and bridesmaid for their aunt Pippa Middleton's wedding to James Matthews in May 2017.
Mia Tindall, Zara and Mike Tindall's eldest daughter, will take up the same position. That is, unless you're Princess Eugenie.
With Princess Beatrice acting as her Maid of Honour, Eugenie hasn't limited her bridal party members to the Royal Family, as she's also asked Robbie Williams and Ayda Field's daughter Theordora Rose to be her bridesmaid.
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Prince George, five, will be joined by fellow page boy Louis de Givenchy - the six-year-old son of JP Morgan banking executive Olivier de Givenchy and his wife Zoe.
But Camilla's surprise absence is reportedly not down to a snub or any bad blood between the royal pair but more a case of clashing diaries.
Eugenie and Jack got engaged in Nicaragua while on holiday at the beginning of 2018.
Mr Brooksbank is a former manager of Mayfair club Mahiki and the couple met while skiing.
But it seems even the royals from Buckingham Palace have their fair share of drama - even where family weddings are concerned.