The Duke and Duchess of Cambridge and Prince Harry attended a church service at St. Pauls Cathedral, which was held by the Queen, to mark the end of British occupation in Afghanistan and to also remember the lives that were lost in battle.

http://www.dailymail.co.uk/news/article-2992974/The-Queen-David-Cameron-lead-tributes-St-Paul-s-memorial-service-honour-453-British-heroes-died-fighting-Taliban.html

The three came colour coordinated in navy blue as they paid their tributes; with Kate Middleton managing to look flawless in her outfit - even while being pregnant! The Duchess arrived in a navy blue dress layered with a knee-length, formal and elegant navy chiara wool coat from British luxury fashion label Beulah London. The Duchess finalised her maternity outfit with a short, low pair of navy blue court heels and matching hat.

http://www.dailymail.co.uk/femail/article-2993312/Kate-s-smile-brave-British-heroes-Duchess-Cambridge-appears-moved-hears-tributes-fallen-soldiers-St-Paul-s.html

Kate Middleton's style is sophisticated and elegant. To me her outfits represent her as a person and how she dresses says a lot about her status and class. Her outfit definitely influences me and makes me want to dress formally. 

http://www.vogue.co.uk/news/2015/03/09/this-week-in-pictures---emma-watson-karlie-kloss-kanye-west/gallery/1377877


http://www.express.co.uk/news/uk/563513/St-Paul-s-Afghanistan-service-Queen-Prince-William-Kate-Middleton

Could this be a trend for navy blue clothing? 
Left to right - Navy Lace V-Lined Dress from Topshop, Eliza J V-Neck Gown With Navy Twist Detail from House of Fraser, Navy Short Sleeved Wrap Top from Next, French Blue Pencil Skirt from BHS, Navy Patent Mid Court Shoes from Faith.