Their strong bond is still evident even as adults, demonstrating a sisterly bond that many people can relate to. At Pippa's wedding in May 2017, her dress was the highlight of the event. However, Catherine and her children, Prince George and Princess Charlotte, also made stylish appearances. Catherine wore a stunning blush pink Alexander McQueen midi dress with long sleeves. Notably, McQueen designed Catherine's wedding dress, which may have added a little extra magic to Pippa's wedding day.

Prince George and Princess Charlotte wore handmade dresses by Spanish brand Paper and Company, reflecting British fabrics. George wore white tights, olive green silk shorts and a long-sleeved white shirt, while Charlotte looked lovely in an ivory silk dress with a matching pink bow tie. In May 2018, Catherine attended the wedding of her best friend Sophie Carter to her husband Prince William. They brought their eldest children, George and Charlotte, who played a key role in the ceremony, as one of three bridesmaids and four page boys.

At the event, George was seen confidently marching alongside the other boys, while the usually outgoing Charlotte kept a low profile. Charlotte was a bridesmaid who scattered the flowers, and was carried by the beaming bride after the ceremony. This is not the first time the young royal couple have taken centre stage at a wedding; they previously attended Meghan Markle and Prince Harry's wedding in May 2018. Sophie Carter has been a close friend of Catherine's for many years, often appearing together at events such as Wimbledon. To honor their friendship, Catherine chose Sophie to be Charlotte's godmother in 2015.

On the same weekend in May 2018, Kate attended Prince Harry and Meghan Markle's wedding at St. George's Chapel in Windsor. There, her children played special roles alongside the children of Harry and Meghan's friends. The pageboys wore miniature versions of the Blues and Royals coats, similar to those worn by Prince Harry and William. For the occasion, Catherine chose a primrose yellow coat by Alexander McQueen, which she first wore at Charlotte's christening and again at Harry and Meghan's wedding. She paired it with beige heels and a flowered hat.

To add a little sparkle to her Anzac Day outfit, Catherine unveiled a new hooped top hat with a black bow, which she paired with her black clutch and heels. She also wore pearl and diamond earrings that belonged to her late mother-in-law, Princess Diana. The stunning earrings were a wedding gift from Collingwood Jewelers. Both Catherine and Prince William wore red poppy brooches, a tribute to servicemen who died in wartime, a tradition that dates back to 1921.