WINDSOR, UNITED KINGDOM - MAY 15: (EMBARGOED FOR PUBLICATION IN UK NEWSPAPERS UNTIL 48 HOURS AFTER CREATE DATE AND TIME) Sophie, Countess of Wessex and James, Viscount Severn attend the final night of The Queen's 90th Birthday Celebrations being held at the Royal Windsor Horse Show in Home Park on May 15, 2016 in Windsor, England. (Photo by Max Mumby/Indigo/Getty Images)