Congratulating Dua Lipa on managing to release a single in such a tough industry, because I thought she was a struggling indie artist. I Googled her the next day and realised that she has 88 million followers.

I don’t get embarrassed.

Playing a pregnant woman, and not being able to find the padding - I shoved a cardie under my dress, and spent the whole play walking around with a sleeve dragging along the floor.

When I was a teenager, I laughed at a joke I didn’t understand. Whoever told the joke turned to me and said, “What are you laughing at?” Of course I didn’t know and he obviously knew I didn’t know. It was excruciating.

Even though I have a highly visual imagination, I’ve had to learn just how much can be said onscreen without a word, and David and Steve have taught me that.

I have to say that I can’t stand lists of ‘must do’s’, whether in life or in writing. Something rebels in me when I’m told what I have to do before I’m fifty, or have to buy this season, or have to write if I want to be a success.

I couldn’t have asked for better collaborators on the stage play than John Tiffany (director) and Jack Thorne (writer).

I try to start work before 9am. My writing room is probably my favourite place in the world. It’s in the garden, about a minute’s walk from the house.

In my early twenties I wrote quite a lot of a very bad novel called The Private Joke. I regularly abandoned it for months at a time to write other things, then picked it up again. Part of the manuscript was sitting up in the luggage rack when, aged 25, I was travelling by train from Manchester to London, and the idea for a very different kind of book hit me: that of a boy who didn’t realise he was a wizard, and was taken off to magic school.

The friends with whom I sat on graduation day have been my friends for life. They are my children’s godparents, the people to whom I’ve been able to turn in times of trouble, people who have been kind enough not to sue me when I took their names for Death Eaters.