LONDON, ENGLAND - MARCH 14:  Catherine, Duchess of Cambridge attends the Commonwealth Observance Day Service on March 14, 2016 in London, United Kingdom. The service is the largest annual inter-faith gathering in the United Kingdom and will celebrate the Queen's 90th birthday. Kofi Annan and Ellie Goulding will take part in the service.  (Photo by Samir Hussein/WireImage)