“Warner Bros. came to me ages ago and said they wanted to do something with Fantastic Beasts. I could see the potential in it. I knew something about Newt, having written a little something for Comic Relief. I had imagined a little bit of back story for him…
So when Warner Bros. came to me and said they wanted to make a film out of the book I had this simultaneous feeling of “it has a lot of potential”, and another feeling of slight panic that “I know some things about Newt and I don’t want you to ruin that for me!” because I knew who he was. So then I went away and sort of dwelt on what I knew about Newt, not intending to write a script but just trying to collect my thoughts so that I could at least give them the backstory I’d imagined, so that their vision was true to what I knew.
Then I really did have one of those moments that always make you phenomenally excited as a writer; but also that you know is going to end up being a ton of work. I thought, “Oh my God, a whole plot’s just descended on me!” But I wanted to do it as I was really excited about it. I wasn’t really thinking about writing the script myself, I thought, you know, I’ll give them this plot and then – fatally – I sat down and thought “I just wonder what it would look like…” and wrote a rough draft in twelve days!
It wasn’t a great draft but it did show the shape of how it might look. So that is how it all started.”
Source: Wonderland Magazine