Britain's Prince William, Duke of Cambridge, (L) and his wife Britain's Catherine, Duchess of Cambridge react as they each hold a pint of Guinness whilst talking with off-duty soldiers from the 1st Battalion Irish Guards, after watching their annual St Patrick's Day parade at Cavalry Barracks in Hounslow, west London on March 17, 2017. / AFP PHOTO / POOL / RICHARD POHLE (Photo credit should read RICHARD POHLE/AFP/Getty Images)
