Kathy Ann Najimy ( born February 6, 1957) is an American actress. She is best known for her roles in the films Sister Act (1992), Hocus Pocus (1993), and Rat Race (2001), as well as her portrayal of Olive Massery on the NBC sitcom Veronica's Closet (1997–2000) and for voicing Peggy Hill on the animated television series King of the Hill (1997–2010).