Denise Donna Nicholas (born July 12, 1944) is an American actress, author, and social activist. Nicholas is known primarily for her roles as high-school guidance counselor Liz McIntyre on the ABC comedy-drama series Room 222 and Councilwoman Harriet DeLong on the NBC/CBS drama series In the Heat of the Night. Prior to her acting career, Nicholas was involved in the Civil Rights Movement during the 1960s.