AARHUS, DENMARK - APRIL 16: Crown Prince Frederik, Crown Princess Mary, Prince Christian, Princess Isabella, Prince Vincent and Princess Josephine attend the 77th birthday celebrations of Danish Queen Margrethe at Marselisborg Palace on April 16, 2017 in Aarhus, Denmark. (Photo by Patrick van Katwijk/Getty Images)

AARHUS, DENMARK - APRIL 16: Crown Prince Frederik, Crown Princess Mary, Prince Christian, Princess Isabella, Prince Vincent and Princess Josephine attend the 77th birthday celebrations of Danish Queen Margrethe at Marselisborg Palace on April 16, 2017 in Aarhus, Denmark. (Photo by Patrick van Katwijk/Getty Images)

AARHUS, DENMARK - APRIL 16: Queen Margrethe, Crown Prince Frederik, Crown Princess Mary, Prince Christian, Princess Isabella, Prince Vincent, Princess Josephine, Princess Marie, Prince Henrik and Princess Athena of Denmark attend the 77th birthday celebrations of Danish Queen Margrethe at Marselisborg Palace on April 16, 2017 in Aarhus, Denmark. (Photo by Patrick van Katwijk/Getty Images)

AARHUS, DENMARK - APRIL 16: Queen Margrethe, Crown Prince Frederik, Crown Princess Mary, Prince Christian, Princess Isabella, Prince Vincent, Princess Josephine, Princess Marie, Prince Henrik and Princess Athena of Denmark attend the 77th birthday celebrations of Danish Queen Margrethe at Marselisborg Palace on April 16, 2017 in Aarhus, Denmark. (Photo by Patrick van Katwijk/Getty Images)

AARHUS, DENMARK - APRIL 16: Prince Henrik, Crown Prince Frederik, Crown Princess Mary, Prince Christian, Princess Isabella, Prince Vincent and Princess Josephine attend the 77th birthday celebrations of Danish Queen Margrethe at Marselisborg Palace on April 16, 2017 in Aarhus, Denmark. (Photo by Patrick van Katwijk/Getty Images)

AARHUS, DENMARK - APRIL 16: Prince Henrik, Crown Prince Frederik, Crown Princess Mary, Prince Christian, Princess Isabella, Prince Vincent and Princess Josephine attend the 77th birthday celebrations of Danish Queen Margrethe at Marselisborg Palace on April 16, 2017 in Aarhus, Denmark. (Photo by Patrick van Katwijk/Getty Images)

AARHUS, DENMARK - APRIL 16: Crown Princess Mary and Prince Vincent of Denmark attend the 77th birthday celebrations of Danish Queen Margrethe at Marselisborg Palace on April 16, 2017 in Aarhus, Denmark. (Photo by Patrick van Katwijk/Getty Images)

AARHUS, DENMARK - APRIL 16: Crown Princess Mary and Prince Vincent of Denmark attend the 77th birthday celebrations of Danish Queen Margrethe at Marselisborg Palace on April 16, 2017 in Aarhus, Denmark. (Photo by Patrick van Katwijk/Getty Images)

AARHUS, DENMARK - APRIL 16: Prince Joachim, Princess Marie, Princess Josephine and Princess Athena of Denmark attend the 77th birthday celebrations of Danish Queen Margrethe at Marselisborg Palace on April 16, 2017 in Aarhus, Denmark. (Photo by Patrick van Katwijk/Getty Images)

AARHUS, DENMARK - APRIL 16: Prince Joachim, Princess Marie, Princess Josephine and Princess Athena of Denmark attend the 77th birthday celebrations of Danish Queen Margrethe at Marselisborg Palace on April 16, 2017 in Aarhus, Denmark. (Photo by Patrick van Katwijk/Getty Images)