The Duchess of Cambridge was pictured helping her sister Pippa Middleton with her train, as was previously done for her at her wedding in 2011.
Kate Middleton escorted the children into the church, telling them to "ssh!" before coming out again to help her sister with her dress.
The picture was reminiscent of the famous one taken at the Duchess' wedding, at which Pippa Middleton wore a very striking dress.
The Duchess struck a more sober note in her long, pink gown and fascinator as she assisted her sister.
was seen telling the page boys and bridesmaids to 'Ssh', with her finger to her lips, as she escorted them in to Pippa Middleton's wedding.
Among them were her own children, Charlotte and George.
The bridesmaids are Countess Philippa Hoyos, Lily French, Avia Horner and Princess Charlotte of Cambridge.
The page boys are Casimir Tatos, Edward Sebire, William Ward and Prince George.
All wore bespoke outfits by Pepa & C.
Prince George and Princess Charlotte looked utterly adorable dressed up as pageboy and bridesmaid for their auntie Pippa's wedding on Saturday.
Princess Charlotte, who has just celebrated her second birthday, walked down the aisle with Miss Middleton on May 20th, at St Mark's Church, Englefield.
Meanwhile, Prince George, who turned four in July, acted as page boy as Pippa marries James Matthews, a 41-year-old hedge fund manager.