TILBURG, NETHERLANDS - APRIL 27: King Willem-Alexander, Princess Ariane and Princess Amalia attend the King's 50th birthday during the Kingsday celebrations on April 27, 2017 in Tilburg, Netherlands. (Photo by Patrick van Katwijk/Getty Images)
TILBURG, NETHERLANDS - APRIL 27: King Willem-Alexander, Princess Ariane and Princess Amalia attend the King's 50th birthday during the Kingsday celebrations on April 27, 2017 in Tilburg, Netherlands. (Photo by Patrick van Katwijk/Getty Images)