New York's Manhattan Theatre Club says Jonathan Walker has replaced the previously announced Sam Robards in its production of "The Assembled Parties."

The company cited unspecified "professional commitments" as the reason for Robards' departure from the world premiere staging of Richard Greenberg's play, which began rehearsals Monday.

Helmed by MTC's artistic director, Lynne Meadow, the cast features Jessica Hecht, Judith Light, Jeremy Shamos, Mark Blum, Lauren Blumenfeld, Alex Dreier and Jake Silbermann.

The limited engagement is to begin previews March 21. Set in New York, the show is to open April 17 at MTC's Samuel J. Friedman Theatre.

"In a sprawling Central Park West apartment, former movie star Julie Bascov and her sister-in-law, Faye, bring their families together for their traditional holiday dinner. But tonight, things are not usual. A house guest has joined the festivities for the first time and he unwittingly -- or perhaps by design -- insinuates himself into the family drama," a synopsis said.

"Twenty years later, as 2001 approaches, the Bascovs' seemingly picture-perfect life may be about to crumble."