The team behind His Dark Materials have revealed why it's taken so long to bring Philip Pullman's books to TV.

The HBO and BBC One adaptation was announced back in 2015, but it won't hit screens until later this year.

Speaking on the His Dark Materials panel at San Diego Comic-Con, executive producer Jane Tranter and writer Jack Thorne (Harry Potter and the Cursed Child) opened up about why it's taken as long as it has.

HBO

"The first thing you've got to do is 'do a PHD' in the author," began Thorne. "So that's what I tried to do with Harry Potter and that's what I tried to do with His Dark Materials, so that when you start adapting, you've got the book already but you've also got a conception of the world inside you."

The writer went on to reveal that he "got it wrong an awful lot" and that they did 46 drafts of episode one.

Tranter then added: "It was a long process – it took us a couple of years to really begin to put the pieces together.

HBO

Related: BBC's His Dark Materials casts Peaky Blinders star in key role

"The BBC came on it right from the start, but as the piece grew and it became more expensive, we looked for more partners to bring on board [and] it was a long conversation with HBO.

"I think part of its appeal for HBO is the very fact that there is nothing else like it on television."

HBO has confirmed that His Dark Materials will premiere this autumn, with BBC One expected to air it later in the year as well.

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