Scott Ellis (The Little Dog Laughed, Curtains) directs the Off-Broadway staging, which will open Nov. 5.

According to Roundabout, "Box office heroes and washed-up has-beens take heed: the play's almost the thing. In this bitingly witty and entertaining comedy by Theresa Rebeck (Mauritius), the lights of Broadway cast an affectionate glow over this look at one of the most notorious roles in the theatre: the understudy."

White (who won the Best Actress Tony for her turn in The Little Dog Laughed, and appeared in TV's "Six Feet Under" and Hollywood's "Transformers") plays Roxanne, a stage manager; Mark-Paul Gosselaar (TV's "Raising the Bar," "Saved by the Bell," "NYPD Blue") is Jake and Justin Kirk (Broadway's Love! Valour! Compassion!, Showtime's "Weeds," the mini-series "Angels in America") is Harry (the title role).

The design team includes Alexander Dodge (sets), Tom Broecker (costumes), Kenneth Posner (lights) and Obadiah Eaves (original music and sound).

The Understudy had its world premiere in July 2008 at the Williamstown Theatre Festival, directed by Ellis, Roundabout's associate artistic known for Twelve Angry Men, Streamers and Entertaining Mr. Sloane.

Rebeck's plays include Mauritius, Our House, The Scene, The Water's Edge, Loose Knit, The Family of Mann, Spike Heels, Bad Dates, The Butterfly Collection, View of the Dome and the Pulitzer Prize finalist Omnium Gatherum. As a television writer, she has written for "Dream On," "Brooklyn Bridge," "L.A. Law," "American Dreamer," "Maximum Bob," "First Wave" and "Third Watch." She has been a writer-producer for "Canterbury's Law," "Smith," "Law and Order: Criminal Intent" and "NYPD Blue."

Tickets to The Understudy are available by calling Roundabout Ticket Services at (212) 719-1300, online at www.roundabouttheatre.org or at the Laura Pels Theatre at the Harold and Miriam Steinberg Center for Theatre box office (111 West 46th Street). Ticket prices range from $70-$80.