The Duchess of Cambridge Kate Middleton has been given a heartwarming nickname by her fans.The 38-year-old mum-of-three has been dubbed the ‘Children’s Princess,’ which appears to be a nod to her late mother-in-law, Princess Diana, who was known as the ‘People’s Princess’. “The Children’s Princess #DuchessofCambridge #KateMiddleton,” tweeted a royal fan alongside a collection of photographs of special moments that The Duchess has shared with children over the years.