She is the daughter of Nicholas John Coombs (Bath, 14 April 1938), a British-born businessman, and his Belgian wife (Uccle, 9 April 1971), Nicole Eva Gabrielle Thérèse, née Mertens (Ixelles, 20 June 1951). Her family relocated to Dion-le-Val, near to Brussels in francophone Wallonia in 1977. She has therefore lived in Belgium since age 3.
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. She is also active in organisations related to the United Kingdom in Belgium. She is a member of the Board of Trustees at the British School of Brussels and actively attends charitable and commemorative events hosted by the British Ambassador to Belgium.
^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.