Both Judith and Camilla are descended from William Keppel, 7th Earl of Albermarle; he is (or was) their great–great–grandfather. His sixth child and third son, George Keppel, married Alice Edmonstone, the daughter of a baronet, in 1891; Alice Keppel met the Prince of Wales (later Edward VII) in 1898 and soon became his mistress. Camilla is the great–granddaughter of George and Alice Keppel. (In other words, Camilla's great–grandmother was the mistress of Edward VII.) Judith is the grand–daughter of the 9th Earl (which probably makes her posher than Camilla, even without the latter's dubious Royal connection); her father was his second son.
© Haydn Thompson 2017