LONDON, UNITED KINGDOM - FEBRUARY 05: (EMBARGOED FOR PUBLICATION IN UK NEWSPAPERS UNTIL 48 HOURS AFTER CREATE DATE AND TIME) Catherine, Duchess of Cambridge and Prince William, Duke of Cambridge take part in a running race against Prince Harry as they join a Team Heads Together London Marathon Training Day at the Queen Elizabeth Olympic Park on February 5, 2017 in London, England. (Photo by Max Mumby/Indigo/Getty Images)