It has been announced that Mark-Paul Gosselaar will headline the new Theresa Rebeck play The Understudy, which begins performances at the Laura Pels Theatre this October. The former Saved By the Bell star, now appearing in TNT’s dramatic series Raising the Bar, will play Jake in The Understudy, while Weeds star Justin Kirk plays the title role. As previously announced, the hilarious Julie White (The Little Dog Laughed) will also be in the cast. The Understudy, which premiered at the Williamstown Theatre Festival in 2008, is the first entry in the Roundabout Theatre Company’s Off-Broadway season. Playwright Rebeck’s other recent works include Mauritius, Our House, Bad Dates, and Omnium Gatherum.