'Saved by the Bell': Tiffani Thiessen Celebrates Kelly's Anniversary with Mark-Paul Gosselaar's Zack

Tiffani Thiessen never forgets an anniversary — even when it's fictional.

Nearly three decades ago, her Saved by the Bell character Kelly Kapowski tied the knot with Mark-Paul Gosselaar's Zack Morris on the TV movie Saved by the Bell: Wedding in Las Vegas — an occasion that Thiessen, 47, marked on her Instagram page Thursday.

"Happy 27th Anniversary Kelly & Zach!" she captioned an old photo of her and Gosselaar, 47. "Way to keep the love going. #friendsforever #tbt."

The original Saved by the Bell ran for four seasons on NBC from 1989 to 1993. Wedding in Las Vegas served as the series finale for the beloved show, airing as a two-hour movie in 1994.

Over the summer, Thiessen posted another Saved by the Bell throwback on Instagram, this one featuring her and costars Lark Voorhies and Elizabeth Berkley posing for the camera in eclectic hats.

GARCIA/Gamma-Rapho/getty Tiffani Thiessan and Mark Paul Gosselaar

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"We should have formed a band. Wait…😜," she captioned the July post, referencing the trio's iconic girl group, Hot Sundae.

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Thiessen, Gosselaar, Voorhies and Berkley all recently reprised their roles from Saved by the Bell for the revival series of the same name that launched on Peacock last November.

Season 2 of the reimagining, which also featured original star Mario Lopez, is currently in production.

The new iteration follows present-day Bayside High students — played by Josie Totah, Mitchell Hoog, Belmont Cameli, Haskiri Velazquez and Alycia Pascual-Pena, among others — with Berkley and Lopez's characters as staffers at the school.

Gary Null/NBCU Photo Bank

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"It's a very special thing we share," Berkley, 49, told PEOPLE of her original Saved by the Bell costars in November. "It's touching to have all these years of people that you care about and that you're rooting for. To be on those same sets with those faces I know and love so well feels like coming home."

When it comes to the new iteration of the hit '90s series, "We wanted to introduce a new cast but also give fun winks and nods for the true fan," she said.

"Saved by the Bell holds a special place in people's hearts. It's part of their childhoods, and that is sacred," Berkley added. "We are all fiercely protective of that legacy."