As Sam Mendes’ stage interpretation of Charlie And The Chocolate Factory opens at the Theatre Royal Drury Lane in London this week, Quentin Blake, writing exclusively for Stylist, reveals how he first brought Willy Wonka to life.

“I confess I can’t help feeling that my visualisation of a Roald Dahl book is the ‘real’ one – partly because I discussed the illustrations with Roald and drew what he wanted; partly because those drawings are what parents and children have known over the years; and partly because when you illustrate a book you live all the parts and come to feel you know them. That doesn’t give me a problem with other versions, for film or stage or in print. They are all works capable of being re-visited, and it’s interesting to see someone else’s take on the work.

It all began over 30 years ago with The BFG. Roald and I had done two books together already, but it was with The BFG that we discovered we needed to talk to each other in more detail. What was the BFG going to wear, for instance? We sat at the dinner table at Gipsy House [Dahl’s home in Buckinghamshire] and talked about it. I did some rough drawings, then a few days later a brown-paper parcel arrived containing one of Roald’s own Norwegian sandals, which became what the BFG wears in the book.

In 1990, after Roald’s death, Penguin Books bought the rights to the books I hadn’t previously worked on and asked me to re-illustrate them. So, no collaborative conversations now, alas; but because I had worked so closely with Roald over 15 years, I felt I had a sense of what he would like. And I wasn’t entirely on my own, because Mrs Dahl [Felicity Crosland] was there for counsel and advice.

With the hair of the Oompa-Loompas, for instance, other illustrators made it fuzzy, curly and hippy – I wanted to make their hair stand on end, to be more spritely and mischievous.

You won’t see it, however in the musical of Charlie And The Chocolate Factory, where the Oompa-Loompas have been re-interpreted yet again for the stage.

I am writing this after my first visit. I’m very pleased to have made a contribution – the show opens with some of my drawings animated to show the story of chocolate; and not only that, but my mind is still bursting with the host of amazements Sam Mendes has created in re-visiting Roald’s imagination.”

Charlie And The Chocolate Factory is on now at Theatre Royal Drury Lane; charlieand thechocolatefactory.com