Allison Janney has joined the cast of the musical comedy, Hairspray for New Line Cinema; she's also made a deal to develop a sitcom at CBS.

Janney will start rehearsals on the film immediatly, says Variety; she'll play Prudy Pingleton, the overbearing mother of Penny (Amanda Bynes) who believes that dancing and having fun is sinful.

The star-studded cast of Hairspray includes John Travolta, Queen Latifah, Christopher Walken, Bynes, Michelle Pfeiffer, James Marsden, Zac Efron and Nikki Blonsky.

Shooting on Hairspray begins next month for a 2007 release.

On the TV side, Janney's deal with CBS is to produce a sitcom for the fall 2007; no details were given as to the plot.