Middleton's choice for her third child is in keeping with the two similarly classic names bestowed upon her son, Arthur, 3, and daughter, Grace, who arrived in March last year.
The pending arrival of little Rose was apparent at the "Party at the Palace" concert for Queen Elizabeth's Platinum Jubilee last month where Middleton attended wearing a bright green dress that showed off her bump.
Rose is the sixth grandchild for Middleton's parents Michael and Carole and another cousin for the Cambridges' royal trio, Prince George, 9, Princess Charlotte, 7, and Prince Louis, 4.
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