Mark-Paul Gosselaar, Justin Kirk join 'Understudy'

FILE- This Nov. 6, 2008 file photo shows actor Mark-Paul Gosselaar posing on the press line at the 8th Annual Discovery Award Dinner hosted by Zimmer Children's Museum in Beverly Hills, Calif. Gosselaar and Justin Kirk will join the already announced Julie White in "The Understudy," a comedy about one of the most underappreciated jobs in theater. (AP Photo/Dan Steinberg,File)