Allison Janney is leaving White House drama The West Wing far behind and joining the cast of the big screen version of Hairspray. Janney, who has won four Emmy Awards for her role as White House Chief of staff CJ GREGG, will begin rehearsals immediately. She will play PRUDY PINGLETON, the overbearing mother of PENNY (Amanda Bynes) who believes that dancing and having fun are sinful. The actress will join John Travolta, Queen Latifah, Christopher Walken, Michelle Pfeiffer and newcomer NIKKI BLONSKY. Production on the film begins next month (SEP06) for a summer 2007 release.