LONDON, UNITED KINGDOM - APRIL 23: (EMBARGOED FOR PUBLICATION IN UK NEWSPAPERS UNTIL 48 HOURS AFTER CREATE DATE AND TIME) Prince William, Duke of Cambridge looks on as Catherine, Duchess of Cambridge high fives a runner dressed as spiderman taking part in the 2017 Virgin Money London Marathon on April 23, 2017 in London, England. The Heads Together mental heath campaign, spearheaded by The Duke & Duchess of Cambridge and Prince Harry, is the marathon's 2017 Charity of the Year. (Photo by Max Mumby/Indigo/Getty Images)