Best known for her popular rhyming stories for children, especially those illustrated by Axel Scheffler, Julia Donaldson is the multi-award-winning author of some of the world’s best-loved children’s books, most notably the modern classic The Gruffalo which has sold over 13 million copies worldwide.

Many of Julia’s books have made the journey from page to stage, and now Zog has joined them. First published in 2010, the book quickly became a bestseller, winning the Galaxy National Children’s Book of the Year Award. Then on Christmas Day 2018, Magic Light Pictures premiered an animated film of Zog on BBC One featuring an all-star cast. And now the keen but clumsy dragon roars his way onto the stage, in a new adaptation from Freckle Productions.

Ahead of Zog flying into Watford Colosseum on Saturday, March 14, and Sunday, March 15, Julia talks about what inspired her to write the book, and now seeing it adapted for the stage.

You’ve written almost 200 books – where do you get your ideas?

It varies, but I always develop the storyline fully in my head before I start writing. I think you read some books and you can tell that people have just made it up as they go along – but I always think, you wouldn’t start telling a joke if you didn’t know what the punchline was.

Where did the idea for Zog the dragon come from?

Well that one was quite unusual, in that the initial idea didn’t come from me. My editor said to me ‘it would be lovely to have a story about a dragon’, so I started thinking about it and the name ‘Madam Dragon’ came into my head.

And then I thought what could Madame Dragon do, who could she be? I came up with various ideas and a schoolteacher was one of them, so I took it from there. Originally it was going to be about a knight and a dragon, but it ended up being about a princess and a dragon – the story came to me bit by bit.

My husband Malcolm, who is a doctor, also had some input here. When I was planning the story, I knew that Zog would keep meeting the princess, and originally I was going to have them play together and toast marshmallows. And Malcolm said couldn’t it be something with a bit more oomph? And then I came up with the doctor angle.

The Knight, Sir Gadabout is one of my favourite comic characters because he’s such an upper-class twit. I love the line he says: ‘I’ve come to rescue Princess Pearl, I hope I’m not too late’ – when it’s actually been a whole year since she was captured.

Your books always have a happy ending. Do you think it’s important to give that to your readers?

I often think about the role of storytelling for young people. In life, not everything does have a happy ending – but I think storytelling is probably very important because to grow up with stories helps you have aspirations, even if life doesn’t turn out like that.

Even as grown-ups, we know that there is a lot of sadness in life, but I think if we didn’t have those stories, aspirations and a sense of what’s ideal, life would be much harder to live.

A lot of your stories are written in verse, what do you feel that adds?

Well obviously if it’s done well, it makes a story very memorable - and people have loved rhyme since time immemorial. I love writing in verse because I wrote songs for so long.

You’ve had a long and very successful working relationship with illustrator Axel Scheffler – how does the partnership work?

It’s always through the editor – I never exchange a word with Axel about the pictures when we’re putting a book together. Axel probably wouldn’t even know that I was writing something until my editor shows it to him – and then I have a nail-biting moment wondering if he likes it and wants to do it.

Then he’ll do some character sketches which I’ll look at. Sometimes, after he’s created sketches for every picture, I’ll think ‘oh hang on, I’m going to change that little bit of text, because I like what he’s done with that’. And then Axel will get to work seriously and I’ll see it at a later stage, when there will still be a few little tweaks.

What’s it like for you when people turn your books into stage performances and films?

For me, it’s like an extension of working with an illustrator. Handing it over to a theatre company or film company you know it’s going to change a bit; the end product will be a blend of my words and their artistic vision.

What do you feel the theatre gives young children?

I remember going to see The Nutcracker when I was a child and I found the whole thing completely magical. I still remember how I felt when the curtain went up.

I suppose in a way it’s the same thing that a book gives you, in that while you’re reading or watching, you believe in a different reality.

Your books are read around the world. What do you think is the appeal?

I don’t know for sure, but I think there are three main things: the storyline – it’s really important to have a well-crafted story; the language; and the illustration – and I do have to give a lot of credit to the illustrators. I think it’s a combination of those three things done well.

Watford Colosseum, Rickmansworth Road, Watford, Saturday, March 14, 3.30pm, and Sunday, March 15, 11am and 2pm. Details: 01923 571102