Mark-Paul Gosselaar appeared on Jimmy Fallon’s show last night in character, as Zack Morris.

Gosselaar played it straight, brilliantly, insisting that he had to change is name from “Zack Morris” because there was already an actor of the same name in SAG. Mark-Paul Zack dished on his failed marriage to Kelly Kapowski, and his ensuing depression and unhealthy friendship with Johnny Dakota.

Making frequent use of “time outs” and addressing the camera one-on-one as he did on Saved By the Bell, Gosselaar also whipped out his familiar giant cell-phone prop to take a call from “Jessie Spano” confirming her participation in a SBTB reunion.

Rising to a challenge from Jimmy, Zack finished with a live performance of “Friends Forever” by SBTB band Zack Attack.