The BBC and Disney + have confirmed long-standing rumours that a new spinoff from Doctor Who will begin filming this month.
The five-part series - called The War Between The Land And The Sea - will star Russell Tovey, who has previously appeared in the main series in two episodes as midshipman Alonso Frame.
Also in the cast is Gugu Mbatha-Raw, another Who alumnus who previously played Tish, sister of companion Martha Jones (Freema Agyeman) - although it is currently unknown if both actors will be reprising their former roles or appearing as new characters.
Returning for the event series are UNIT chief Kate Lethbridge-Stewart (Jemma Redgrave) and Colonel Ibrahim (Alexander Devrient), although it is also currently unknown whether other UNIT staff including Mel Bush (Bonnie Langford), Rose Noble (Yasmin Finney) and Morris Gibbons (Lenny Rush) will be joining them.
A synopsis for the spinoff, which is rumoured to feature the Sea Devils, reads: "When a fearsome and ancient species emerges from the ocean, dramatically revealing themselves to humanity, an international crisis is triggered. With the entire population at risk, UNIT step into action as the land and sea wage war."
Showrunner Russell T Davies, who has penned the new show with Pete McTighe, said: "I'm so lucky to work with such a magnificent cast. And this is a huge, muscular, thrilling drama which will shake The Whoniverse to its foundations. When the Doctor's not in town, the whole of humanity is in trouble."
BBC drama director Lindsay Salt added: "The War Between The Land and The Sea is another utterly unique and gripping drama from Russell T Davies and we're delighted to welcome the show to The Whoniverse!
"Featuring a stellar cast, with Russell Tovey and Gugu Mbatha-Raw taking on leading roles, this brand new epic mini series will leave audiences on the edge of their seats as they watch UNIT take on one of their biggest battles to save humanity."
A release date for the show has yet to be confirmed although it is likely to go out towards the end of 2025 after the new series of the main show airs in early 2025.
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