1. How do you manage two very different fictional worlds (Cormoran Strike and the Wizarding World) and two very different formats (books and screenplays)?

I’ve never had any problem moving between fictional worlds, even if I’m working on them simultaneously. There can be a lot of hanging around waiting for notes on the draft of a movie script, so I like to have a novel on the go in the background.

I envision the different fictional worlds as different rooms to which I have access. At worst, when entering one of the rooms, I have to spend a bit of time re-orientating myself, finding my bearings again, checking what I’ve put in which drawers. However, they’re discrete places in my head, and the moment I re-enter one of the worlds, the characters are as fully real to me as when I left them. Cormoran Strike has never reached for a magic wand, and Newt Scamander doesn’t limp or drink Doom Bar.

The difference between screenplays and novels is more challenging. It isn’t that one is intrinsically easier than the other, but that I’m far less used to writing the former, whereas novels and I are old friends.

2. What comes first, plot or character? 

I’m most interested in character, but plot usually comes first. I need to know the broad outline of the story before I start hatching characters. Having said that, a couple of stories have grown out of a single character. Character can be plot.

3. How do you come up with titles and how important are they?

Titles usually suggest themselves, but coming up with them always make me nervous. I think they’re quite important, which adds pressure. I have no idea what the third Beasts movie will be called, even though I already know the whole story. On the other hand, I already know the titles of the fifth Galbraith book and the children’s story I’m writing next.

4. Does the process of making film and TV put pressure on you to write faster, and do audiences’ reactions influence where you go with plot and how you develop characters? 

Fan reactions to Harry Potter were both exhilarating and overwhelming, often at the same time. I saw it as my job back then to make sure that I arrived at the ending I had planned for the series before the first book was even published. The final destination was hugely important to me, for reasons that were both personal and artistic, and I plotted a course towards it despite being subjected to a lot of (almost entirely good-natured) buffeting from readers.  Part of the fun of a series is the way people invest in the relationships from book to book (or film to film), and I love the fact that people have strong opinions on what should happen next. On the other hand, I never set pen to paper without knowing way more than will eventually appear on the page or screen, and I usually have a fairly strong idea of where I’m going, that won’t change.

In the case of the Beasts movies, I’m writing original screenplays, so there’s a practical need for the work to be done by a specific date so that filming can commence on time.

Where the Cormoran Strike novels are concerned, and even though I love the TV adaptations, I still finish the novel when it’s ready, no sooner! When I agreed to the books being adapted for TV I made it clear that the books would come as and when Robert Galbraith chose. Luckily, he loves writing them, so we should hopefully be seeing Strike on TV for some time to come.

5. Why choose Twitter rather than a well-placed press article or interview to make your opinions known?

Well, firstly that assumes that my main objective in tweeting is to ‘make my opinions known’ rather than what I think most people’s reason is for being on Twitter, which is to engage with other people, to debate and joke. I think for a lot of well-known people, it’s a bracing dose of normality.  Nobody’s shy about telling you you’re an idiot. Twitter’s a great leveller. It isn’t for everyone, but nearly all the writers I know love it, because they’re in their own medium.

There’s a time and a place for a press article, but tweeting is something that happens for me on writing breaks. At its best, it’s fun and fascinating. People in all their diversity and strangeness interest me more than anything else on the planet, and Twitter is as good a place as I’ve ever found for seeing human nature in the raw!