The Duke And Duchess Of Cambridge & Prince Harry Attend The Mix Christmas Party [Getty Images]

LONDON, ENGLAND - DECEMBER 19: Catherine, Duchess of Cambridge, Prince William, Duke of Cambridge and Prince Harry attends a Christmas party for volunteers at The Mix youth service on December 19, 2016 in London, England. The Mix youth service works with Their Royal Highnesses' Heads Together Campaign. (Photo by Danny Martindale/WireImage)

WireImage Danny Martindale