Not only is Kate Middleton a descendant of coal miners, she's also the cousin of cousins of Beatrix Potter.
This item was published under the headline "KATE'S SECURITY INCREASED AS POTTER LINKS REVEALED." Is it really that dangerous to be related to relatives of a kid-lit author?According to a genealogy expert quoted by the Daily Express, "Kate is a descendant of a well-heeled Leeds dynasty, the Luptons, and is a cousin of two Lupton sisters - Elizabeth and Elinor - who were cousins of Miss Potter. They received illustrated greetings cards from the author in the early days of the Twentieth century." [Link]

Kate Middelton is a cousin of Bessie and Elinor Lupton, who were cousins of Beatrix Potter. There is no direct blood link between Miss Middleton and the authoress.
I suspected as much. That's why I was careful to say "cousin of cousins," and "related to relatives."