Princess Eugenie was invited to take pictures with a bride and groom after she was spotted walking past their ceremony on Friday (07.07.17).
The 27-year-old royal was walking down the street outside a registry office in Maidstone, Kent, south east England, when newlyweds Ben and Emily Shaw spotted her as they were tying the knot and invited her to take pictures with them.
The brunette beauty duly obliged and the new Mrs. Shaw was delighted with their surprise guest.
Emily, 31, is quoted by Kent Online as saying: "We're just in Maidstone for the day and are having the proper wedding back home in London tomorrow.
"This was such a shock, I couldn't believe it. It was so nice of her to take photos with us."
The happy couple were only planning a "low-key" event, but their big day turned into national news.
Ben, 30, quipped: "We thought today would be a low-key affair before the big day tomorrow with family and friends, but this was amazing."
Like their double wedding days, the pair also have two honeymoons in the diary.
Firstly, they are heading to Majorca before their main post-nuptials celebration in Sri Lanka later this year.
Eugenie may have her own wedding to attend in the near future as there was speculation last year that she had got engaged to boyfriend Jack Brooksbank.
She is said to have introduced Jack to Queen Elizabeth, who reportedly described Jack as a "thoroughly nice young man" and gave the couple their blessing.