LONDON, UNITED KINGDOM - FEBRUARY 06: (EMBARGOED FOR PUBLICATION IN UK NEWSPAPERS UNTIL 48 HOURS AFTER CREATE DATE AND TIME) Catherine, Duchess of Cambridge attends the Place2Be Big Assembly with Heads Together for Children's Mental Health Week at Mitchell Brook Primary School on February 6, 2017 in London, England. (Photo by Max Mumby/Indigo/Getty Images)
LONDON, UNITED KINGDOM - FEBRUARY 06: (EMBARGOED FOR PUBLICATION IN UK NEWSPAPERS UNTIL 48 HOURS AFTER CREATE DATE AND TIME) Catherine, Duchess of Cambridge attends the Place2Be Big Assembly with Heads Together for Children's Mental Health Week at Mitchell Brook Primary School on February 6, 2017 in London, England. (Photo by Max Mumby/Indigo/Getty Images)
LONDON, UNITED KINGDOM - FEBRUARY 06: (EMBARGOED FOR PUBLICATION IN UK NEWSPAPERS UNTIL 48 HOURS AFTER CREATE DATE AND TIME) Prince William, Duke of Cambridge and Catherine, Duchess of Cambridge attend the Place2Be Big Assembly with Heads Together for Children's Mental Health Week at Mitchell Brook Primary School on February 6, 2017 in London, England. (Photo by Max Mumby/Indigo/Getty Images)
LONDON, UNITED KINGDOM - FEBRUARY 06: (EMBARGOED FOR PUBLICATION IN UK NEWSPAPERS UNTIL 48 HOURS AFTER CREATE DATE AND TIME) Prince William, Duke of Cambridge and Catherine, Duchess of Cambridge attend the Place2Be Big Assembly with Heads Together for Children's Mental Health Week at Mitchell Brook Primary School on February 6, 2017 in London, England. (Photo by Max Mumby/Indigo/Getty Images)
LONDON, UNITED KINGDOM - FEBRUARY 06: (EMBARGOED FOR PUBLICATION IN UK NEWSPAPERS UNTIL 48 HOURS AFTER CREATE DATE AND TIME) Catherine, Duchess of Cambridge attends the Place2Be Big Assembly with Heads Together for Children's Mental Health Week at Mitchell Brook Primary School on February 6, 2017 in London, England. (Photo by Max Mumby/Indigo/Getty Images)
