Mario Lopez and Tiffani Thiessen are remembering their on-screen principal, Dennis Haskins, with touching tributes after the “Saved By The Bell” star’s death.

Mario — who played A.C. Slater on “Saved By The Bell” — says he’s “heartbroken to hear about my old friend Dennis Haskins.”

He continued … “If you knew him, you loved him — and if there was karaoke, you knew Dennis was getting on that mic!”

Mario added … “I’m grateful for the laughs, the memories, and the friendship we shared all these years. Rest easy, my friend. You’ll always be part of our Bayside family.”

Tiffani — who played Kelly Kapowski alongside Dennis’ Mr. B — said he was a steady presence in her teenage years … and “will always remember his kindness.”

Mario and Dennis were both featured in all 86 episodes of the show … with Tiffani joining then in 76 of those episodes across all 4 seasons from 1989-1992.

The 75-year-old was known for playing Mr. Belding on the popular sitcom, trying to keep the Bayside High kids out of trouble with his catchphrase … “Hey, hey, hey, what is going on here?”