Mr. BeldingJimmy Fallon likes to bring together '90s high school sitcom casts. When he failed to reunite the students of Bayside High from 'Saved by the Bell,' he held a reunion for the next best thing -- the cast of 'California Dreams.'

Only there was an unexpected guest. Bayside High principal Mr. Belding -- played by Dennis Haskins -- showed up while Fallon was introducing the actors.

"Dennis, you weren't in 'California Dreams,'" Jimmy tells Haskins. Watch: