Once the children had followed Meghan down the aisle of St George's Chapel, they were scurried away into a side room and were not present for the full marriage service.
The newly weds - who will now be known as the Duke and Duchess of Sussex - reportedly chose the classic hit as Meghan had previously called it her "happy song", according to a source.
Britain's Princess Charlotte arrives at the chapel.
Princess Charlotte is among six bridesmaids and her brother Prince George is one of four page boys.
Princess Charlotte, the daughter of Duke William and Duchess Kate, isn't shy when it comes to the camera.
Cheeky Prince George, aged four, looked adorable as he lined up alongside Jasper, six, Brian Mulroney, seven, and John Mulroney, seven. The adorable dresses worn by the royal wedding flower girls were designed by Clare Waight Keller in the Givenchy Haute Couture Atelier in Paris, and were made to look like miniature replicas of the bride's gown. Each dress is sculpted in Ivory silk Radzimir, and is high-waisted with short puff sleeves and hand finished with a double silk ribbon detail tied at the back in a bow.More news: 'US can't decide for the world:' Rouhani rejects Pompeo's Iran demands
More news: Maduro declared victor in disputed Venezuela election
More news: Messi: Neymar joining Real Madrid would be a bad blow for Barca
Meghan Markle at her wedding ceremony. "They feel so lucky to have been able to share their day with all those gathered in Windsor and also all those who watched the wedding on television across the UK, Commonwealth, and around the world".
The 58-year-old writer - who was married to Prince Andrew from 1986 to 1996 - reportedly turned the Hollywood hunk down when he approached her, according to the Mirror Online.
The mini-Meghans are wearing white leather Aquazurra shoes with the cutest touch: bridesmaid's pair is monogrammed with their initials and the wedding date.
Today was an exciting day for Princess Charlotte of Cambridge. Eventually, it was decided that Duchess Kate would walk with the children into the chapel. "She has a very close-knit group of friends and did not want to choose one over the other", Jason Knauf, communications secretary to Prince Harry, was quoted as saying earlier this month.