Kavner joined the troupe prior to rehearsals, after Michael Stahl-David withdrew from the production.

Moses' science-minded play begins performances Aug. 19. The cast also includes Brian Avers, Aubrey Dollar and Meredith Forlenza.

Pam MacKinnon (Clybourne Park at PH, The Four of Us, Occupant, Peter and Jerry) directs the new work by the author of The Four of Us and Bach at Leipzig.

Opening night is Sept. 13. Performances are scheduled through Sept. 25 at Playwrights Horizons' Mainstage Theater at 416 W. 42nd Street.

Here's how PH characterizes Completeness: "How does a computer scientist hook up with a molecular biologist? He blinds her with science, of course. When Elliot (Kavner) builds a computer program to help Molly (Dollar) with her research project, the variables in their evolving relationship shift as rapidly as the terms of their experiment. This deft and imaginative new ROM-comedy shows that even the most sophisticated algorithm may freeze in the face of life's infinite possibilities."

The production features scenic and costume designs by David Zinn, lighting design by Russell H. Champa and original music and sound design by Bray Poor. Production stage manager is Charles M. Turner III.

Completeness received its world premiere earlier this year at South Coast Repertory.

Avers appeared in Broadway's Rock 'n' Roll and The Lieutenant of Inishmore; Dollar was in PH's Juvenilia, plus Bottom of the World for Atlantic Theatre Company; and Forlenza's credits include Broadway's A Behanding in Spokane and Pal Joey.

For tickets, visit www.TicketCentral.com or call (212) 279-4200, or in person at the Ticket Central Box Office, 416 West 42nd Street (between Ninth & Tenth Avenues). Visit playwrightshorizons.org.