The part might even expand into a regular role when the legal drama evolves into a new series next season, the Web site noted.
Before "The Practice" ends this spring, new attorney Alan Shore, played by James Spader, has a showdown against the attorneys of Young, Frutt & Berluti over his recent termination, and enlists the help of another firm, whose senior partner is played by William Shatner.
Best-known for her roles in "Risky Business" and "The Hand that Rocks the Cradle," De Mornay will play another attorney at the new firm.
When "The Practice" ends, Shore and Tara Eilson, played by Rhona Mitra, are expected to join the new firm, and De Mornay will have the option to continue as a regular, Zap2it.com said.
2014: The Year in Music [PHOTOS]