Stephen King isn’t clowning around.
The horror mastermind behind the 1986 novel “It” was a guiding force on “It: Welcome to Derry,” the highly anticipated HBO prequel series set decades before the events of the original 2017 and 2019 films.
Expanding the mythology of Pennywise and the cursed town of Derry, Maine, the series found new terror under King’s quiet supervision.
Andy Muschietti, who helmed both blockbuster “It” films and returned once again to direct alongside his sister Barbara Muschietti, said that the King of Horror served as both a guardian and a collaborator throughout the show’s production.
“I think he was as involved as with the films, but also from a very reasonable perspective,” Muschietti, 52, told The Post. “He’s not controlling everything we do, even though he’s blessing and screening everything that we show him.”
The director added that King, 78, wasn’t just signing off from the sidelines, but that the best-selling author was genuinely excited about what was coming on the small screen.
“I think he’s excited,” Muschietti continued. “He’s very open to that exploration because we’re not doing a faithful account of everything that happens in the book.”
“But we’re also sort of completing the puzzle and creating new storylines and giving life to something that didn’t have a conclusion,” the “Flash” filmmaker shared. “So he’s very open and excited about what we do.”
And while the legendary writer didn’t shy away from giving notes, it turned out that those were rare yet always spot on.
“Of course, he’s obviously verbal when he doesn’t like something,” Muschietti admitted. “But most of the time, he seems very excited and open to this creation.”
Barbara Muschietti, meanwhile, praised King for both his creative generosity and his personality off the page.
“He’s a great human being, too,” she gushed.
Brad Caleb Kane, who serves as showrunner alongside Jason Fuchs, went a step further and credited King with “godfathering” the new “It: Welcome to Derry” prequel series.
“He was reading scripts as they rolled off the line, reading story documents, reading treatments, and he would point to them and say yay or nay,” Kane, 52, told The Post. “If things bumped him, he would tell us, and we would look at it.”
“When Stephen King tells you a story point doesn’t work, you look at it and you change it, because he’s usually right and he always was in this case,” the “Extinction” star, 52, continued.
Kane added that King’s involvement was nothing less than helpful, especially as he, the Muschiettis and Fuchs further navigated the world of Derry for the next project in the franchise.
“He was basically very generous with his creation and with his universe,” the “Banker” writer shared. “He said: ‘Here it is. I’ve written it all down – play around in it.’”
“We shared it with him as we wrote it,” Kane added, “and he guided us.”
After revealing that King would even weigh in on casting choices, Fuchs shared how he and his fellow creators learned that they earned the modern-day master of the macabre’s stamp of approval.
“We wanted to do something that he’d feel good about and be proud of,” the “Argylle” writer, 39, said. “We were thrilled, this past week, he put out a Thread saying he’d seen it and loved it. And episode one was terrifying.”
“That was a great way to go into this whole launch of the show,” he concluded. “It was very, very exciting to see.”
King’s influence, however, wasn’t limited to just guidance behind the scenes.
Kimberly Guerrero, a new cast member joining “It: Welcome to Derry” as the character Rose, revealed how one scene from the new prequel series in particular connected her to the “It” author.
“For me, it was really this meta moment because one of my favorite moments in the movie is when King makes an appearance,” the actress, 58, said regarding King’s cameo in the 2019 film. “He makes an appearance in Second Hand Rose.”
“So to get to play Rose and to get to be in that exact space…and I believe I’m even sitting on the side of the counter where Stephen was sitting,” she told The Post.
Guerrero further explained how that scene not only connected the new prequel to “It” and “It Chapter Two,” but also tied the Derry setting together throughout the entire franchise.
Like the original films, “It: Welcome to Derry” was shot almost entirely on location in Port Hope, Ontario.
“So it felt very intentional and really profound to get to be in that space, because this space holds that energy,” she said. “It remembers that story.”
“It was a real gift to get to circle back and join in on the story that’s already being told and even take it deeper and take it back further,” Guerrero added.
As for how the requel series originated, Muscietti revealed that the idea began while he was still shooting “It Chapter Two” more than five years ago.
“We didn’t want to say goodbye,” the “Mama” director explained. “I was having conversations with Bill Skarsgård about how cool it would be to tell the story of the origins of Pennywise, how It became a clown. When did that happen?”
Skarsgård portrayed Pennywise in the 2017 and 2019 films. He returned for the prequel and serves as an executive producer this time around.
“And that evolved later, into the idea of making it into a series that comprised a bigger, fuller story that would give more justice to the entire story told in the book,” Muscietti continued, “but also an opportunity to answer a lot of the questions and cryptic messages not answered in the book intentionally.”
“And that’s how it all started,” he added.
“It: Welcome to Derry” premieres on HBO and begins streaming on HBO Max on Sunday, Oct. 26.
