Claire Waldoff (Clara Wortmann, Gelsenkirchen, Germany, October 21, 1884 – January 22, 1957) was a famous German cabaret singer and entertainer in Berlin during the 1910s and 1920s. Wortmann was born the eleventh child of 16. Her parents owned a tavern in Gelsenkirchen. After completing school, she studied theatre and chose as her pseudoynm Claire Waldoff. In 1903, she got her first theatre jobs in Bad Pyrmont and in Kattowitz.