"A Discovery of Witches" finally premiered on Sundance Now and Shudder Thursday, and it’s been a long wait for some fans. Author Deborah Harkness’ bestselling novel was released in 2011, and her All Souls trilogy has fans all over the world who have been asking for an adaptation for nearly a decade.

The drama follows Diana Bishop (Teresa Palmer), a historian who wants to ignore her magical heritage. However, when the witch finds an enchanted manuscript that every supernatural creature seems to want, she might start rethinking her stance on magic. One of the many people interested in her recent discovery is a very handsome vampire, Matthew Clairmont (Matthew Goode).

Harkness spoke to International Business Times about the TV adaptation of "A Discovery of Witches." The author and executive producer revealed how the show came together and her admiration for the creative team. She also teased her favorite changes that were made to the book and her cameo in the TV show.

IBT: This isn't the first time you got an offer to adapt "A Discovery of Witches," right?

Harkness: It isn't. My first offer to adapt it, that I accepted, came from Warner Bros. The first plan was to make this into a film. Lots of people worked really hard, and at the end of our 18-month development process, we all looked at each other and I think we all felt the same thing, which was this is never going to get smashed into a 90-minute film and have it be something that we're proud of or that the fans embrace. So, at that point, I had a lot of other things to do, and I ended up putting it on hold for a while.

When the time came for me to start thinking about it again, I was approached by Jane Tranter at [production company] Bad Wolf who really does superb adaptations. She's done Dickens and all kinds of things. She really convinced me that she would remain true to the spirit of the book, which was really important to me because, as you say, of all those readers [who embraced the story].

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Matthew Goode and Teresa Palmer star in "A Discovery of Witches." AMC Networks

IBT: How involved in the show are you?

Harkness: I'm an executive producer. I was involved with the story conferences early on in the process, so I was on set. I helped with the series overview, or series bible is what they sometimes call it. Just was sort of a general resource in my role as executive producer as well as the content creator.

IBT: Did you get a say in the casting of Matthew and Teresa, or did they just bring that to you?

Harkness: I did get a say in it. On a television project, no one has real control. I think my fans always say, "Did you control the casting?" No, because it's a collaborative creative process. Nobody controls it, but I did have input for sure. I was just so thrilled with the casting of both of them. They just embody these characters. People say, "They look right." Well, it goes so far beyond look. What you need is for somebody to be able to convincingly occupy their skin. This is what Teresa and Matthew do so brilliantly in the show.

Deborah Harkness
Deborah Harkness is excited for U.S. audiences to finally see "A Discovery of Witches," which debuted in the U.K. last year. She is pictured at Comic-Con on July 19, 2018 in San Diego, California. Mike Coppola/Getty Images

IBT: Would you want to write "A Discovery of Witches" episodes in the future?

Harkness: I would love to write episodes. I feel like I would need a fair amount of help because I would be a newbie at it. Just like when I first wrote "A Discovery," it was 1,100 pages long. A book person had to gently explain to me that really it couldn't be that long and have anyone read it. [Laughs] I would need help as a newcomer, but I would love to do that. I love writing dialogue, and I love delving into characters, and coming up with great plot twists, so it would be a lot of fun if they were ever interested in that.

IBT: Will you make a cameo in the series?

Harkness: I do make a cameo in the series. I was told it was tradition, so yes. Sharpe-eyed viewers will see a cameo of me, but I'm not going to say anything more than that. They'll have to look for it.

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Author Deborah Harkness was involved behind-the-scene of "A Discovery of Witches" as an executive producer. Matthew Goode is pictured during filming. AMC Networks

IBT: What was most important for this show to get right in your eyes?

Harkness: For me it's really about the characters. I'm OK and expect there to be a fair amount of monkeying around with the plot in order to get it changed from [a book to a TV show]. The book is a first-person narrative. It has a lot of reflection. You couldn't really do that unless there were voice-overs all the time, which would not be great television. For me, it wasn't so much about the plot specifics, which I knew were going to have to change in some instances, but what was really important to me were the characters. The characters needed to feel true to the characters in the book because, again, I have been blessed with having a very enthusiastic and supportive fanbase. They love these characters. I needed to know that those characters were going to remain essentially, not in every detail maybe, but essentially at their core the same.

IBT: Like you said, every adaptation has to make all these changes to it to really fit the medium. Where there any changes that you were particularly happy about or found really creative?

Harkness: Oh yeah. Just watching the writers, and also the set people, read through the book and think, 'OK, wait a minute, can we pull up something, for example, about Diana's parents and put it earlier?' So, there's just some wonderfully poignant and thrilling and goose pimply, exciting moments. That was something that Diana thought about in her head, but I wasn't sure how they were going to manage to convey that visually on the screen. The writers were so creative at the ways that they wove Diana's mother and father into the narrative from the beginning. Again, I'm not going to spoil it too much for viewers, but they were done with such amazing elegance, and yet they're so forceful and so compelling when you see them. It really resonates in a way that was just so thrilling to see.

IBT: What was the coolest moment to see come to life from your books on screen?

Harkness: Probably a moment where Diana is feeling extremely emotional. She's very frustrated and she's also very sad, and she conjures up something called witch water. It's where she basically becomes a storm. Seeing the way that they did that was just so amazing. Again, our special effects department was superb at using a light hand. Sometimes I think special effects can be overdone, if that makes sense. Sometimes less is more. I was just so thrilled with the way that they did that.

The other thing that just absolutely blew me away were the sets. James North, our designer was nothing short of a genius. When I walked into the Bodleian Library set, when it was under construction or walked into the Bishop house once it was finished, it was almost spooky. I at one point looked at a block of painted plywood, and I said, "I know what that is." They said, "What is that?" I said, "That is the third column base from the entrance at Duke Humfrey's [a reading room in Oxford’s Bodleian Library] which has a really distinctive wooden grain." They had replicated everything down to the grain of wood in the columns.

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Valarie Pettiford, Teresa Palmer and Alex Kingston star in "A Discovery of Witches." AMC Networks

IBT: That's crazy.

Harkness: It was crazy. They rebuilt the Selden End of Duke Humfrey's in a studio in Cardiff. I believe it was three or four inches short of the actual building, and that was because they needed to leave room for a crane. Otherwise, it was so exact. That was a real wow moment. I think it's a good thing I never saw the whole set. I never was able to walk onto the whole completed set. The timing just didn't work out. I was there when it was being built, and I was there when it was being struck, but I wasn't there when it was whole and complete. I think it's probably a good thing because I think I would have just been overcome.

IBT: That was actually my next question. The set very much looks like Oxford. Did you guys actually get to go to Oxford and film?

Harkness: We did film at Oxford. We filmed exteriors at Oxford, and we filmed some interiors at Oxford. We also used a lot of very beautiful Welsh substitutes for Oxford because we were a Wales-based television team. It was just prohibitive given the amount of action that takes place in the Bodleian, and the restrictions in the Bodleian for obvious reasons having to do with their library patrons about when we could film. We could only film basically when the library was closed on weekends. No more than 25 people, including the camera crew and the actors, could be in the room at the same time. It wasn't going to work.

That's where the genius of the art department, and James North and his team came in because they just said, "Well no problem. We'll just build it." When they first said that to me, I was just dumbfounded. I said, "You can't just build it. Everyone will know it's not the Bodleian. There's no way." There are a few little giveaways. The floors are different. Some of the windows are slightly different, but they did an amazing job. Amazing.

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Oxford's Bodleian Library is a big part of "A Discovery of Witches." Teresa Palmer is pictured in front of the Radcliffe Camera. AMC Networks

IBT: How is the TV show adapting the book in terms of timeline? Is the first season the entire first book?

Harkness: Yes, the first season is the first book. It covers it in eight episodes, and that really gives us room to establish the world and establish the characters. As I said, the story is not told strictly from Diana's point of view, so it allows us to delve into the stories and experiences of some of the characters we get to know better in subsequent books or we may always have had lots of questions about as readers. On the day Diana picks up the book in Oxford, the question becomes, OK, well what was Peter Knox doing that day? Was he just sitting around twiddling his thumbs waiting for something to happen? No. He was going about his life. What does that life look like? So this gave us lots of great opportunities, I think, and the writers real room to spread their wings and explore.

IBT: Do you see the show going just for three seasons, or would you like to see it go beyond the books?

Harkness: Well, that's going to be up to Sky and Sundance, our U.K. and U.S. broadcast partners. I certainly hope that it can cover the trilogy. [Editor's Note: "A Discovery of Witches" was renewed for Seasons 2 and 3 after this interview.] I think what will happen after that will up to the actors and to the powers that be, and it will be about success and a will to go on. I can certainly imagine lots of ways in which it can continue. The world keeps expanding with the new book ["Time’s Convert," which came out in September]. I think it will be interesting to see what kind of added life television gives to it.

Some readers, believe it or not, are just experiencing it for the first time. I was reminded at a recent book event that readers who are now, say, 20 were 12 when "A Discovery of Witches" came out. So they're getting to the books that maybe their mom read for the first time. It's kind of cool to see, with "Time’s Convert" and with the television show, a new generation of readers coming to the story.

IBT: Speaking of "Time's Convert," do you think that it could be turned into a spinoff TV show eventually?

Harkness: Oh, I think it could if everybody was willing. It's a great story… Marcus is such a great character, and Phoebe is fascinating. They are younger. They're in their early 20s, as opposed to their 30s like Diana and Matthew. It's got a very different kind of feeling and a different vibe to it, and it might make great television. Who knows? We'll have to see where that goes.

"A Discovery of Witches" Season 1 is available on Sundance Now and Shudder.

This Q&A has been edited for length and clarity.