Over the years, as the children have grown, it's been noted how much Princess Charlotte resembles the late Queen Elizabeth II and Lady Sarah Chatto as children.
And one photograph of Princess Charlotte caused Prince William to do a double-take in 2020, when he thought it was an image of himself as a young boy.
But as we've looked back through the archives, we've also seen similarities between a young William and his youngest child, Louis.
The images were taken on the Sandringham estate in January 1988, when William would have been the same age as Louis now.
William's outfit and inquisitive expression are strikingly similar to Louis, as you can see in this photograph taken of Louis last Christmas.
The Prince and Princess of Wales are currently taking a break from their royal duties to enjoy the school summer holidays with their children.
George, Charlotte and Louis are all pupils at Lambrook school in Berkshire, close to the family's Windsor home, Adelaide Cottage.
It's not known whether the Waleses have decided to spend time abroad this summer or whether they are staying at their Norfolk abode, Anmer Hall.
The family-of-five have also enjoyed staycations on the Isles of Scilly off the Cornish coat in recent years.
King Charles and Queen Camilla have begun their break in Scotland, and William and Kate, and their children, are expected to join them at Balmoral at some point in August.
Where was George, Charlotte and Louis' last public engagement?
Carlos Alcaraz ended up victorious during the nail-biting five-hour match with Novak Djokovic, and George and Charlotte were just as animated as their parents with their reactions in the royal box.
The young royals also got to meet the new Wimbledon champion after the match, with Charlotte spotted having a shy moment backstage.
Just a few days before the final, George, Charlotte and Louis all enjoyed an end-of-term treat as William and Kate took them to the Royal International Air Tattoo show in Fairford, Gloucestershire.
George especially was in his element as they were shown the different aircraft and automobiles on display.