MONTE-CARLO, MONACO - MARCH 18: In this handout image provided by Le Palais Princier, Beatrice Borromeo and Pierre Casiraghi attend a dinner during the Rose Ball 2017 To Benefit The Princess Grace Foundation at Sporting Monte-Carlo on March 18, 2017 in Monte-Carlo, Monaco. (Photo by Le Palais Princier/SBM via Getty Images)

MONTE-CARLO, MONACO - MARCH 18:  In this handout image provided by Le Palais Princier, Beatrice Borromeo and Pierre Casiraghi attend a dinner during the Rose Ball 2017 To Benefit The Princess Grace Foundation at Sporting Monte-Carlo on March 18, 2017 in Monte-Carlo, Monaco.  (Photo by Le Palais Princier/SBM via Getty Images)

MONTE-CARLO, MONACO - MARCH 18: In this handout image provided by Le Palais Princier, Beatrice Borromeo and Pierre Casiraghi dance during Rose Ball 2017 To Benefit The Princess Grace Foundation at Sporting Monte-Carlo on March 18, 2017 in Monte-Carlo, Monaco. (Photo by Le Palais Princier/SBM via Getty Images)

MONTE-CARLO, MONACO - MARCH 18:  In this handout image provided by Le Palais Princier, Beatrice Borromeo and Pierre Casiraghi dance during Rose Ball 2017 To Benefit The Princess Grace Foundation at Sporting Monte-Carlo on March 18, 2017 in Monte-Carlo, Monaco.  (Photo by Le Palais Princier/SBM via Getty Images)

MONTE-CARLO, MONACO - MARCH 18: Pierre Casiraghi and Beatrice Borromeo attend the Rose Ball 2017 To Benefit The Princess Grace Foundation at Sporting Monte-Carlo on March 18, 2017 in Monte-Carlo, Monaco. (Photo by Stephane Cardinale - Corbis/Corbis via Getty Images)

MONTE-CARLO, MONACO - MARCH 18:  Pierre Casiraghi and Beatrice Borromeo attend the Rose Ball 2017 To Benefit The Princess Grace Foundation at Sporting Monte-Carlo on March 18, 2017 in Monte-Carlo, Monaco.  (Photo by Stephane Cardinale - Corbis/Corbis via Getty Images)

MONTE-CARLO, MONACO - MARCH 18: Pierre Casiraghi and Beatrice Borromeo attend the Rose Ball 2017 To Benefit The Princess Grace Foundation at Sporting Monte-Carlo on March 18, 2017 in Monte-Carlo, Monaco. (Photo by Stephane Cardinale - Corbis/Corbis via Getty Images)

MONTE-CARLO, MONACO - MARCH 18:  Pierre Casiraghi and Beatrice Borromeo attend the Rose Ball 2017 To Benefit The Princess Grace Foundation at Sporting Monte-Carlo on March 18, 2017 in Monte-Carlo, Monaco.  (Photo by Stephane Cardinale - Corbis/Corbis via Getty Images)

MONTE-CARLO, MONACO - MARCH 18: Pierre Casiraghi and Beatrice Borromeo attend the Rose Ball 2017 To Benefit The Princess Grace Foundation at Sporting Monte-Carlo on March 18, 2017 in Monte-Carlo, Monaco. (Photo by Stephane Cardinale - Corbis/Corbis via Getty Images)

MONTE-CARLO, MONACO - MARCH 18:  Pierre Casiraghi and Beatrice Borromeo attend the Rose Ball 2017 To Benefit The Princess Grace Foundation at Sporting Monte-Carlo on March 18, 2017 in Monte-Carlo, Monaco.  (Photo by Stephane Cardinale - Corbis/Corbis via Getty Images)