LONDON, ENGLAND - FEBRUARY 06: Catherine, Duchess of Cambridge and Prince William, Duke of Cambridge attends the Guild of Health Writers conference on February 6, 2017 in London, England. (Photo by Danny Martindale/WireImage)
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) Catherine, Duchess of Cambridge talks with school children as she 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)
The Duke and Duchess of Cambridge leave the Mitchell Brook Primary School, north London, where they attended the Place2Be Big Assembly with Heads Together for Children's Mental Health Week. (Photo by John Stillwell/PA Images via Getty Images)
