Doctor Who spoilers follow.
Doctor Who boss Russell T Davies has offered a cryptic clue for the future.
The writing has taken back the helm of Doctor Who for a series of 60th-anniversary specials starring David Tennant and Catherine Tate, followed by an all-new series starring Ncuti Gatwa and Millie Gibson as The Doctor and companion Ruby Sunday.
While the focus for many fans is the 60th anniversary later this year, Davies is already generating excitement by offering a three-word tease for what follows in 2025.
Related: Doctor Who's Ncuti Gatwa confirms Hollywood star is "biggest fan" of show
In his Letter from the Showrunner in Doctor Who Magazine, RTD confirmed that he's already started work on series 15 - which is expected to air in 2025.
Davies wrote that the words "garden", "firmament" and "diploma" all contain clues about what to expect in series 15, so make of that what you will.
The producer has already lined up an impressive group of guest stars, including Drag Race's Jinkx Monsoon as a mysterious villain and the return of Bonnie Langford as classic series companion Mel Bush.
Other notable guests will include EastEnders legend Anita Dobson and It's a Sin's Michelle Greenidge, Hamilton star Jonathan Groff and Am I Being Unreasonable?'s Lenny Rush, plus Jemma Redgrave will be back as UNIT boss Kate Stewart.
Russell T Davies also recently dropped some hints about Jinkx Monsoon's villainous character, revealing "not everyone is getting out of this alive" following The Doctor and Ruby's showdown with the baddie.
"Jinkx Monsoon as. well who can that be?! SO much fun! So much terror," the writer wrote.
Doctor Who returns later in 2023 on BBC One in the UK and Disney+ elsewhere. Meanwhile, in the US, the show airs on BBC America, with series 1-12 available on Max.