Eddie Redmayne: Well, what I found kind of riveting was, I thought when I joined this film that there would be people [who] go, “Well, this is how it’s gonna be done.” But the amazing thing about director David Yates and David Heyman, the producer, is -- despite the scale of these films, and they worked on many of the Potter films -- there is an intimacy to the creation of it that feels really collaborative.

J.K. Rowling wrote this script and yet she allowed us to come up with ideas. So when it came to the beasts I remember David Yates saying, “Well, why don’t you spend a few weeks, months working out what would be best for you?” I ended up working with all sorts of puppeteers. Some of the guys who had worked on “War Horse” came up with huge puppets.

And then sometimes there were actors dressed in green-screen things for me to interact with. And then sometimes it was just imagining. There’s one little guy called Pickett who is a Bowtruckle. I kind of adore him. He’s a sweet little stick insect figure. And they made a little wire puppet for me to rehearse with. So I did a couple of weeks’ rehearsal. Then in the end I would just sort of imagine he would stand on my hand. And I’d just find myself on the tube, on the subway kind of gently talking to imaginary figures!