The long-standing, BBC cult classic Doctor Who is expanding the franchise once more with two new spin-offs that directly tie into the overarching “Whoniverse”. Details surrounding one of the series have finally come to the surface as The Daily Mirror reported on Wednesday that a Kate Stewart spin-off is underway. Portrayed by Jemma Redgrave, the Head of Scientific Research at UNIT has been featured as a recurring character in Doctor Who since 2012. According to the exclusive, the forthcoming sci-fi series will focus on Kate’s tenure as head of the organization.

The military research organization was first introduced in 1966 and has appeared within the flagship series periodically through the years. UNIT — which stands for Unified Intelligence Taskforce — investigates extraterrestrial and supernatural threats to Earth and has become more integral within the Whoniverse since its mention in the Doctor Who 2005 reboot. Ahead of their series release, audiences will get a taste of what’s to come in the Redgrave-led series when Kate and her team return for the upcoming Doctor Who Christmas special which serves as the introduction to the 15th incarnation of the iconic Time Lord.

Although no official premiere date has been confirmed, audiences may not have too long of a wait. Principal shooting for the series has already begun as Redgrave was seen filming scenes with Millie Gibson — who portrays Ruby Sunday — for the upcoming sci-fi adventure series in January. Returning showrunner Russel T. Davies has high hopes for the Doctor Who offshoot, proclaiming that one of the completed episodes is “one of the greatest things [he’s] made in [his] life.”

Details about the second spinoff are still forthcoming, but sources close to the project have confirmed that the series will be “a monsters spin-off.”

Related: Doctor Who: Where You Should Begin if You Want to Start the Series

Doctor Who Showrunner Assures The Franchise Will Remain True to Its Roots

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The Whoniverse’s recent expansion can largely be credited to the international distribution deal that was struck with Disney+, which additionally fostered the return of Doctor Who’s showrunner, Russell T. Davies. His second return to the franchise marks a revival of sorts for Doctor Who, one that coincides with the new era Ncuti Gatwa is ushering in as the first Black Doctor to helm the franchise. Though Disney+’s involvement means global audienceship and more money to put towards production, fans of the beloved franchise began to question whether American involvement would change the series’ integrity. In a recent issue of Doctor Who Magazine, Davies quelled any concern about the deviation from the franchise’s roots and teased the return of a past character.

“I know people are, naturally, worried about American producers having notes on things. Well, don't be. They're giving excellent notes. And I'm here to tell you, you haven't watched a drama on British television in 20 years that hasn't had American notes on it. Everything is a co-production...it’s really, completely normal.”

Additionally, Davies teased the possible return of the Guardian of the Solar System, Mavic Chen. The treacherous villain was portrayed by the late Kevin Stoney and hasn’t made an appearance in the series since the 1960s.

“And if you want any more reassurance, let me just tell you that we're about to transmit the words Mavic Chen on television for the first time since 1966. It is absolutely the same show.”