Henriëtte Adriana "Hetty" Blok (6 January 1920 – 6 November 2012) was a Dutch cabaret artist, singer, and actress who performed on the stage, on radio, and on television for more than five decades. Her best-known role is Nurse Klivia, one of the lead roles in the iconic television series Ja zuster, nee zuster, a role with which she was identified the rest of her life. She was known also as a friend of Annie M. G. Schmidt and a singer of her songs.