LONDON, ENGLAND - AUGUST 30:  (L-R) Catherine, Duchess of Cambridge, Prince William, Duke of Cambridge and Prince Harry are seen during a visit to The Sunken Garden at Kensington Palace on August 30, 2017 in London, England.  The garden has been transformed into a White Garden dedicated in the memory of Princess Diana, mother of The Duke of Cambridge and Prince Harry.  (Photo by Chris Jackson/Getty Images)