As the long-awaited feature film take on The Dark Tower is poised to open at the box office, the potential TV series is taking a big step forward.

Glen Mazzara (The Walking Dead) has been tapped to serve as showrunner on the TV adaptation of the ambitious Stephen King series. The TV take, envisioned as a straight-to-series project, is currently in its early stages and tapping a showrunner is the key first step. A network is not yet attached. Sources tell The Hollywood Reporter that it is being eyed for a short-order (between 10 and 13 episodes) and a home on cable or streaming outlets by producers Media Rights Capital and Sony Pictures Television. Production is eyed to begin in 2018, though nothing is locked in given all the variables.

"I’ve been a Stephen King fan for decades and the opportunity to adapt The Dark Tower as a TV series is a great honor," Mazzara tells THR. "The events of The Gunslinger, Wizard & Glass, The Wind Through the Keyhole, and other tales need a long format to capture the complexity of Roland's coming of age — how he became the Gunslinger, how Walter became the Man in Black, and how their rivalry cost Roland everything and everyone he ever loved. I could not be more excited to tell this story. It feels like being given the key to a treasure chest. And oh yeah, we’ll have billy-bumblers!"

The feature film, which opens Friday and is already generating mixed reviews, is considered to be independent from the TV series — though there is some overlap. Slated to appear in the series are Idris Elba, who stars as Roland Deschain (aka the Gunslinger); Dennis Haysbert (as Roland's father, Steven Deschain); and young star Tom Taylor (Jake Chambers, the son-like figure to the Gunslinger). The potential TV series will revolve around a younger Roland and his group — with those roles currently uncast. The TV entry will be based on Wizard in Glass, the fourth book in The Dark Tower series. While insiders do not see the potential TV series as a prequel, an origin story is more appropriate to describe the vision for the project.

Akiva Goldsman — who was originally slated to pen the script when the TV series was set up at Universal — is attached to exec produce alongside his Weed Road Pictures president of production Gregory Lessans. Imagine TV's Ron Howard and Brian Grazer are also on board as exec producers. Feature film director Nikolaj Arcel and co-writer Anders Thomas Jensen are collaborating on the script. Mazzara will oversee day-to-day operations on the ambitious project.

Mazzara was The Walking Dead's second showrunner, coming in to replace Frank Darabont on the AMC zombie drama. His TV credits include A&E's Damien as well as Crash, The Shield and Life. He's repped by CAA.

The Dark Tower is in theaters Friday.

As part of the effort, Amazon made a mega deal for a Lord Of the Rings TV series and is developing a slew of high-profile titles, including The Dark Tower, Wheel of Time, Ringworld, Lazarus and Snow Crash.

Amazon’s adaptation of Stephen King’s The Dark Tower book series has found its Gunslinger. Sam Strike (Nightflyers) has been cast as the lead, Roland Deschain, in the project, which I hear is nearing a formal pilot order at the streaming platform.

Jasper Pääkkönen (Vikings, BlacKkKlansman) will co-star in the drama, from executive producer/showrunner Glen Mazzara and MRC. The project had had a blinking green light for a couple of months, with casting quietly underway. It had been in development at Amazon for almost a year.

The Dark Tower TV series is independent from the film and is meant to be a more faithful retelling of the book than the movie was. I hear it will take place many years before the events depicted in the feature and will focus on Roland Deschain’s (Strike) origin story – how he first became a gunslinger and got his guns, his first conflict with the man in black, his first love and his first mission as a gunslinger.

Pääkkönen is believed to be playing Marten, the character Roland is out to kill.

The 2017 Sony/MRC feature The Dark Tower starred Idris Elba as Roland Deschain.

King’s eight Dark Tower books draw from multiple genres, including dark fantasy, science fantasy, horror, and Western.

Strike is coming off a series regular role on the Syfy/Netflix series Nightflyers, based on the novella by George R.R. Martin. The English actor launched his acting career with main roles on the British series M.I. High and EastEnders. He will next be seen in the HBO/Sky miniseries Chernobyl and will reprise his guest starring role on the second season of David Fincher’s Netflix series Mindhunter. He is repped by Gersh, Circle of Confusion and UK’s The Artists Partnership.

Finnish actor Pääkkönen played Halfdan the Black on History’s Vikings and recently co-starred in Spike Lee’s BlacKkKlansman.

Michael Rooker has been cast in the Amazon Studios adaptation of Stephen King’s The Dark Tower, currently filming the pilot episode on location in Croatia.

Rooker’s role in the series pilot is still being kept under wraps, but there is no lack of information and speculation around the much-anticipated series. Variety previously reported that Sam Strike will play Roland Deschain, aka The Gunslinger, while Jasper Pääkkönen is believed to be playing The Man in Black, also known as Randall Flagg.

The series will consist of a total of 13 episodes, developed by Glen Mazzara (The Walking Dead), Akiva Goldsman (Titans, Star Trek: Discovery) and writer Stephen King. The Dark Tower will tell the story of how Roland became a gunslinger and his first encounter with the villainous Man in Black. The Dark Tower is scheduled for release in 2020.