LONDON, UNITED KINGDOM - MAY 01: (EMBARGOED FOR PUBLICATION IN UK NEWSPAPERS UNTIL 24 HOURS AFTER CREATE DATE AND TIME) Catherine, Duchess of Cambridge arrives to officially open the new Anna Freud Centre Of Excellence on May 1, 2019 in London, England. The Duchess of Cambridge is Patron of the Anna Freud National Centre for Children and Families. (Photo by Max Mumby/Indigo/Getty Images)

LONDON, UNITED KINGDOM - MAY 01: (EMBARGOED FOR PUBLICATION IN UK NEWSPAPERS UNTIL 24 HOURS AFTER CREATE DATE AND TIME) Catherine, Duchess of Cambridge (clutch detail) arrives to officially open the new Anna Freud Centre Of Excellence on May 1, 2019 in London, England. The Duchess of Cambridge is Patron of the Anna Freud National Centre for Children and Families. (Photo by Max Mumby/Indigo/Getty Images)

BALLYMENA, NORTHERN IRELAND - FEBRUARY 28: (EMBARGOED FOR PUBLICATION IN UK NEWSPAPERS UNTIL 24 HOURS AFTER CREATE DATE AND TIME) Catherine, Duchess of Cambridge visits CineMagic at the Braid Arts Centre on February 28, 2019 in Ballymena, Northern Ireland. Prince William last visited Belfast in October 2017 without his wife, Catherine, Duchess of Cambridge, who was then pregnant with the couple's third child. This time the couple concentrate on the young people of Northern Ireland. Their engagements include a visit to Windsor Park Stadium, home of the Irish Football Association, activities at the Roscor Youth Village in Fermanagh, a party at the Belfast Empire Hall, Cinemagic - a charity that uses film, television and digital technologies to inspire young people and finally dropping in on a SureStart early years programme. (Photo by Max Mumby/Indigo/Getty Images)

LONDON, UNITED KINGDOM - OCTOBER 31: (EMBARGOED FOR PUBLICATION IN UK NEWSPAPERS UNTIL 24 HOURS AFTER CREATE DATE AND TIME) Catherine, Duchess of Cambridge visits the Imperial War Museum to view family letters from World War One on October 31, 2018 in London, England. (Photo by Max Mumby/Indigo/Getty Images)

LONDON, UNITED KINGDOM - FEBRUARY 13: (EMBARGOED FOR PUBLICATION IN UK NEWSPAPERS UNTIL 24 HOURS AFTER CREATE DATE AND TIME) Catherine, Duchess of Cambridge attends a 'Mental Health In Education' conference at Mercers' Hall on February 13, 2019 in London, England. The conference will bring together delegates from across the mental health and education sectors to explore and discuss the benefits of collaborative working and what more can be done to tackle mental health issues in schools. (Photo by Max Mumby/Indigo/Getty Images)

WOKINGHAM, UNITED KINGDOM - JULY 10: (EMBARGOED FOR PUBLICATION IN UK NEWSPAPERS UNTIL 24 HOURS AFTER CREATE DATE AND TIME) Catherine and Duchess of Cambridge attends the King Power Royal Charity Polo Match, in which Prince William, Duke of Cambridge and Prince Harry, Duke of Sussex were competing for the Khun Vichai Srivaddhanaprabha Memorial Polo Trophy at Billingbear Polo Club on July 10, 2019 in Wokingham, England. (Photo by Max Mumby/Indigo/Getty Images)

LONDON, UNITED KINGDOM - MARCH 12: (EMBARGOED FOR PUBLICATION IN UK NEWSPAPERS UNTIL 24 HOURS AFTER CREATE DATE AND TIME) Meghan Markle attends the 2018 Commonwealth Day service at Westminster Abbey on March 12, 2018 in London, England. (Photo by Max Mumby/Indigo/Getty Images)

LONDON, UNITED KINGDOM - JULY 17: (EMBARGOED FOR PUBLICATION IN UK NEWSPAPERS UNTIL 24 HOURS AFTER CREATE DATE AND TIME) Meghan, Duchess of Sussex and Prince Harry, Duke of Sussex visits The Nelson Mandela Centenary Exhibition at the Southbank Centre on July 17, 2018 in London, England. The exhibition explores the life and times of Nelson Mandela and marks the centenary of his birth. (Photo by Max Mumby/Indigo/Getty Images)