HBO is weighing up the possibility of more seasons of Philip Pullman fantasy adaptation His Dark Materials after the Bad Wolf and New Line-produced show became the WarnerMedia network’s biggest ever co-viewing hit.

HBO President of Programming Casey Bloys told Deadline that the show, which launched in November, has performed very well, cumulating to 5M viewers an episode. “One of the things that I was hoping and the numbers we’re seeing bear this out, it is more of a co-viewing show than we’ve ever had. We don’t have many shows where kids and parents can watch together and that was the idea with this show and it has done really well.”

His Dark Materials stars Dafne Keen, James McAvoy, Ruth Wilson and Lin-Manuel Miranda. Keen plays main character Lyra, a seemingly ordinary but brave young woman from another world. The first season follows Lyra searching for a kidnapped friend. She uncovers a sinister plot involving stolen children and becomes a quest to understand a mysterious phenomenon called Dust. As she journeys through the worlds, including our own, Lyra meets a determined and courageous boy called Will (Amir Wilson). Together they encounter extraordinary beings and dangerous secrets, with the fate of both the living — and the dead — in their hands.

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HBO and the BBC, which co-produced the show, initially gave the series a 16-episode, two-season order. The first two seasons, written by Jack Thorne, are essentially based on the first two books in the novel series, Northern Lights and The Subtle Knife, although Thorne admitted he had “stolen” a few “treats” from other books.

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Although Thorne admits that he has “stolen” a “few treats” from other books, the first two seasons are essentially based on Northern Lights and The Subtle Knife. Now, HBO and the BBC must decide whether to greenlight a third season. The third book, The Amber Spyglass, follows Lyra at 16, which would tie up with filming in 2021. “Season two is just coming in and I think once we get season two, we’ll talk about season three and what it would look like. We obviously have to talk to the BBC,” added Bloys.

Bad Wolf co-founder Jane Tranter previously told Deadline that if ordered, she would like to split the “huge” and “sprawling” book into two seasons.

The show, which is co-financed by Anton, has also performed well in Britain with the opening episode watched by more than 7.2M viewers, making it the biggest new drama launch on British TV in more than five years. The final episode came to a close with just over 4M overnight viewers.