It was inevitable: Zack Morris — sorry, Mark-Paul Gosselaar — was going to find himself in a New York theater one of these days. But we never would have imagined that the circumstances would be so perfectly, mind-blowingly meta. This fall, Gosselaar will star in Theresa Rebeck’s The Understudy, alongside Vulture pal Julie White and Weeds’ Justin Kirk, as a low-level movie star named Jake, helicoptered into an otherwise doomed Broadway production of a rediscovered Kafka play. Kirk plays the embittered title character and White the (naturally) very harried stage manager; the play’s Godot is an unseen $20-million-a-gig icon whom Gosselaar’s character (best known for an action film in which his salient line is “Get in the truck!â€) nakedly envies. The play is both hilarious and existentially sad. Yeah, we know — Saved by the Bell, Part Two. We’re perfectly confident Gosselaar can pull off the emotional range and evoke the conflicted feelings of a star who feels he hasn’t quite earned his keep. We’re only disappointed Dustin Diamond didn’t land the role of understudy.