Mary Steenburgen heads to '30 Rock'

Mary Steenburgen has signed on to play the mother of Elizabeth Banks' character, reports Entertainment Weekly. Steenburgen will stick around for multiple episodes as Charlotte, Avery's "highly spirited and attractive mother."

Look for the ultra-WASPY Charlotte to clash with Irish Catholic Jack (Alec Baldwin).

Also cast in Season 6 of the NBC comedy are Denise Richards in an unknown role and James Marsden in a six-episode arc. Will Arnett will also stop by, reprising his role as Devon Banks.

Steenburgen can now be seen on husband Ted Danson's HBO comedy "Bored to Death."