 After Tricia Dickson, Katrina Johnson and Alisa Reyes left "All That", the producers brought in Danny Tamberelli, Leon Frierson, and Christy Knowings.Knowings had previously been a performer on a Rosie O'Donnell sketch-comedy special produced by Nickelodeon entitled, "And Now This".She and her twin brother, actor Chris Knowings, were in the Rosie O'Donnell special greenroom, unaware that two casting directors from "All That" were in the room.