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!”) 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.