Sister Sledge is an American R&B and pop music group. It was founded in Philadelphia in 1971. They have had several hit singles. Their hits are We are Family, Frankie and He's the Greatest Dancer. Their names are Kim, Kathy, Joni and Debbie. Sledge is their actual last name. The original identity of the group was "Mrs. Williams Grandchildren", though it was later changed to the current name "Sister Sledge". They were especially popular in the late 1970s and early 1980s.