She is a daughter of Nicholas John Coombs, a British-born businessman, and his Belgian wife, Nicole Eva Gabrielle Thérèse, née Mertens. Her family relocated to Dion-le-Val, near to Brussels in francophone Wallonia in 1977. She has therefore lived in Belgium since age 3.
As a member of the royal family, Princess Claire has been awarded the Order of Leopold. She takes part in public events such as the celebrations for Belgium's National Day, and royal family events such as weddings and christenings.
Unlike her two sisters-in-law, Mathilde and Astrid, Claire has no defined official role.
She occasionally appears in public accompanying her husband, generally in support of environmental causes or animal charities. She is also a leading patron of the Brussels Choral Society, which sang at the religious part of her marriage ceremony.
Claire Coombs received the title Princess of Belgium from the King ten days before her marriage, by Royal Decree of 1 April 2003 (effective as of the date of the wedding, on 12 April 2003). This title is no longer automatic for a consort since a Royal Decree of 1991, abrogating the 1891 Royal Decree that accorded the wife of a Prince of Belgium the feminine version of that title upon approved marriage.