It’s official. Sarah Michelle Gellar has signed on to reprise her role as Kathryn Merteuil in NBC’s revival of “Cruel Intentions.” The actress posted the news Wednesday night on her Instagram.

Should the pilot get picked up, Gellar will be a series regular — in fact, she’s first on the call sheet.

NBC’s “Cruel Intentions” series kicks off 15 years after the film ended, centering around Gellar’s all-grown-up Kathryn, as she vies for control of Valmont International, as well as the soul of Bash Casey (newcomer Taylor John Smith), the son of the late Sebastian Valmont (the character that was played by Ryan Phillippe in the ’90s film) and Annette Hargrove (the character played by Reese Witherspoon). Upon discovering his late father’s legacy in a hidden journal, Bash is introduced to a world of sex, money, power and corruption he never could have imagined.

For the modern-day revival, Kathryn’s character is described as a “smart, sexy, cruel, charismatic, powerful” master manipulator. The woman behind the scandal involving Bash’s mother, Annette, Kathryn is now married to the wealthy Pascal Barrett and spearheads an inspiring youth rehabilitation movement, as well as being involved in a local private school. She is privately shaken by the arrival of Sebastian’s son, Bash, and the re-appearance in her life of the girl she wronged years ago, Annette.

Roger Kumble, the original writer and director of “Cruel Intentions,” will direct the pilot, which was likely appealing to Gellar, knowing she’ll be in good hands, reuniting with the film’s original visionary. Her Instagram post tonight included a photo of her with Kumble and exec producer Neal Moritz from the original production juxtaposed to one in present day, gearing up for the new NBC production. “I am happy to say that I will be joining them,” she wrote.

Kumble co-wrote the pilot with Lindsey Rosin and Jordan Ross, who were behind L.A.’s “Cruel Intentions” musical last year, which drew Gellar — plus Witherspoon and Selma Blair — to a show this past summer. At that show, Gellar told the duo how much she liked their adaptation of “Cruel,” though the TV project had not yet been put into development. Kumble, Rosin and Ross will all exec produce the potential series, along with Moritz and Pavun Shetty of Original Film. Sony Pictures Television is the studio.

Though Witherspoon’s character is still alive in the world of “Cruel Intentions,” the Oscar-winner was not approached to reprise her part, and the role of Annette is currently being cast.

Unlike many stars who have returned to recent reboots of their former projects for guest roles, such as Bradley Cooper in “Limitless,” NBC’s “Cruel Intentions” reboot is centered around Kathryn, the character made famous by Gellar, and though the part was not written specifically for her, the show’s team had been courting the actress to sign on ever since the pilot was ordered.

“Cruel Intentions” marks a major return to TV for Gellar, who has starred in two network shows since “Buffy the Vampire Slayer” went off the air: “The Crazy Ones” with Robin Williams in 2013 on CBS and “The Ringer” in 2011 on the CW. Both series only lasted one season. Gellar starred on “Buffy” for seven seasons, starting in 1997. Shortly after, she became the “it” girl of the ’90s, landing lead roles in teen cult favorites “I Know What You Did Last Summer” and then “Cruel Intentions” in 1999. She is repped by ICM.

Drop Dead Diva star Kate Levering has been tapped to play the role Reese Witherspoon originated in the 1999 teen drama for NBC’s Cruel Intentions pilot, EW has learned.

Picking up 15 years after the events of the film, the new Cruel Intentions finds Kathryn Merteuil (returning star Sarah Michelle Gellar) vying for control of Valmont International, as well as the soul of Bash Casey (Taylor John Smith), the son of her late stepbrother Sebastian Valmont (portrayed in the film by Ryan Phillippe) and Annette Hargrove (portrayed in the film by Witherspoon). After discovering his late father’s legacy in the infamous journal, Bash is introduced to a world of sex, money, power, and corruption he never could have imagined.

Levering’s Annette Hargrove Casey is described as a genuine, good Christian woman for whom life has not been easy. Annette lives in a small town with her husband, Trevor Casey, and her son, Bash, with whom she has a close and playful relationship. Annette is rocked by Trevor’s sudden and scandalous death, and Bash’s discovery that his biological dad was the billionaire hotel magnate Sebastian Valmont, with whom Annette had a torrid relationship when she was in high school. Annette’s life starts to unravel when Bash heads to San Francisco to meet his birth family, putting Annette face-to-face with her nemesis, Kathryn Merteuil.

The news comes on the heels of Gellar reprising her role as the master manipulator Kathryn for the pilot, and sticking around as a series regular should Cruel Intentions get picked up. This, of course, raises the question: Why no Witherspoon? Reports have it that the Cruel Intentions brain trust did not approach the Academy Award winner, who is an executive producer on the untitled ABC pilot that brings Grey’s Anatomy alum T.R. Knight back to the network.

The film’s director, Roger Kumble, will helm and co-write the Cruel Intentions pilot alongside co-writers Jordan Ross and Lindsey Rosin. The movie’s writer, Neil Moritz, will also serve as an executive producer, as will Pavun Shetty. Sony Pictures Television and Original Film will produce the pilot.