The Hogwarts Express is picking up speed and new details about HBO’s Harry Potter series are revealed this week.

During a presentation on Thursday at Warner Bros. Discovery’s headquarters in London, HBO boss Casey Bloys revealed that filming for the multi-stage series – first announced in 2023 – is set to begin filming in mid-2025 at Warner Bros.’s Leavesden Studios in the UK , where the eight-part film saga was also filmed. The presentation also revealed new details about the show’s casting and duration.

Here’s everything we know so far.

When is it coming?

The series is expected to debut on Max and streaming services HBO and Warner Bros. Discovery in 2026 – nearly 30 years since the first book in JK Rowling’s best-selling series was published in 1997 and 15 years after the last film hit the screen came.

Who does it?

It’s a British affair: The showrunner will be Francesca Gardiner, best known for her writing work on seasons three and four of the HBO series Succession. She also served as executive producer of the HBO and BBC co-production His Dark Materials (adapted from Philip Pullman’s fantasy novels) and the second season of Killing Eve.

Gardiner, who will also take on the role of executive producer, was selected by Warner Bros. after a months-long selection process that invited a number of creatives to pitch ideas for the Harry Potter series.

Fellow Brit Mark Mylod, director and executive producer of Succession, will serve as director and executive producer of the series.

Will JK Rowling be involved?

Yes. Warner Bros. is producing the series in association with Rowling’s company Brontë Film and TV, and Rowling is one of the series’ executive producers.

Rowling owns responsibility for key aspects of the Harry Potter IP – namely the characters – meaning Warner Bros. had to make a deal with her to greenlight her series.

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And her involvement was controversial from the start. Rowling’s views on trans people have drawn criticism in recent years from the LGBTQI+ community, fans of her books and even some of the stars of the Harry Potter films.

Still, Bloys said Thursday that he was “completely satisfied” with Rowling’s involvement and was “not worried about consumer reaction.”

Who will be on the show?

HBO has not confirmed a cast at this time, but various trade publications have begun revealing who is in the running. Variety reports that Warner Bros. has contacted Mark Rylance to play Dumbledore. The Hollywood Reporter reported sources confirming that Paapa Essiedu was offered the role of Severus Snape. There are also rumors that Cillian Murphy is being considered for Voldemort.

The young protagonists of the books, however, will all be unknown. In September, Warner Bros. released an open casting call for Harry, Ron and Hermione, looking for actors who will be between the ages of nine and 11 in April 2025 and reside in the United Kingdom or Ireland. Actors had to submit two self-tapes: one with a short introduction and one with a short story or poem.

Mylod announced Thursday that its casting team is currently reviewing 32,000 submissions for the children’s roles.

“We will look at every single video,” he said, adding that the team is currently reviewing between 500 and 1,000 tapes daily and hopes to “shortlist some of our candidates” in January.

What is the vision for the series?

Dark. Remember, Mylod is the guy who directed not only the psychological warfare in “Succession,” but also episodes of “Game of Thrones” and the horror-infused foodie satire “The Menu.” Gardiner has reportedly spoken in the past about how she doesn’t like patronizing children and sanitizing horror.

The show was touted as a faithful adaptation of Rowling’s series, and the author herself praised HBO for its commitment to “preserving the integrity” of her books, saying the new adaptation “will allow for a level of depth and detail only available from… “A long TV series is on offer”.

How many seasons?

From the start, Warner Bros. referred to the series as “a decade-long series” – suggesting it might not be as clear-cut as one season per book.