Queen Elizabeth II. Princess Elizabeth as Junior Commander in the ATS inspecting The Motor Transport Training Centre at The future Queen Elizabeth II served in the Auxiliary Territorial Service (ATS), becoming the first female member of Britain’s royal family to serve as a full-time active member of the armed forces. (NCJ Archive/Mirrorpix/Mirrorpix via Getty Images) NCJ Archive/Mirrorpix/Mirrorpix via Getty Images