Prince George and Princess Charlotte join aunt Pippa Middleton's bridal party

Prince William's children Prince George and Princess Charlotte have landed roles as members of their aunt Pippa Middleton's bridal party for her upcoming wedding.

Pippa, the sister of William's wife Catherine, Duchess of Cambridge, will exchange vows with financier James Matthews on 20 May (17), and her royal niece and nephew will be playing key parts in the ceremony, held at St. Mark's Church in Englefield, England, near the Middleton family home.

A representative for William and Catherine's London residence, Kensington Palace, confirms three-year-old Prince George will serve as a page boy, while little Charlotte, who turns two on 2 May (17), will be a bridesmaid.

It is not believed the Duchess will be a part of the bridal party, preferring instead to let her kids shine alongside their aunt, who caught the world's attention by wearing a figure-hugging Alexander McQueen dress as Catherine's maid of honor at her 2011 wedding to Prince William.

Among the other guests in attendance will be Prince William's brother, Prince Harry, although it is not yet known if his actress girlfriend Meghan Markle will be joining him for the formal family celebration.

Pippa, 33, and her 41-year-old fiance, the brother of British reality star Spencer Matthews, became engaged last July (16) during a romantic weekend getaway to the U.K.'s Lake District, where James popped the question with a diamond sparkler reportedly worth over $250,000 .

They had been dating for less than a year, but had previously enjoyed a brief romance back in 2012.