In the 2017 TV documentary Diana, Our Mother: Her Life and Legacy, Prince William and Prince Harry openly talk about their mother Princess Diana (†36) and their relationship with her.
Prince William also discusses how he tells Prince George, Princess Charlotte and Prince Louis about her. He said that he and his wife, Duchess Catherine, have many photos of Diana in their house. When he tucks George, Charlotte and Louis in at night, he regularly tells them about his mother, who died in 1997.
Prince William talks to his children about "Grandma Diana"
For Duchess Catherine this is not possible, of course, as she has never met Diana. But Prince William frequently reminds their children that they have two grandmothers!
"I just try and remind them that there are two grandmothers in their lives, and so it's important that they know who she was and that she existed," the Duke of Cambridge said. We miss the late Lady Diana everyday.