How We Met: Steven Butler & Francesca Simon

Francesca Simon, 55

A bestselling children's author, Simon is known for her hugely popular 'Horrid Henry' series, which has spawned its own animated TV show and West End theatre production. She lives in London with her husband

I first saw Steve during a rehearsal for the theatre production of Horrid Henry three years ago. He was cast as the main character, Henry, and the first thing I noticed was what an amazing dancer he was; so graceful and fluent. I loved the production and how Steven didn't try to soften the nastiness of the character.

When the show transferred to the West End, Steve was committed elsewhere. I was so sad to hear he was leaving that after his last show, I offered to buy him lunch, which is when we discovered we had so much in common; we both love to cook – and we're both into museums.

There was a sculptures exhibition on that we both wanted to see, so I suggested we go together. From then on, we started seeing each other all the time – cooking for each other, going to see plays – and he became one of my best friends. Of course we are aware it is an unusual friendship; while we don't feel the age difference, we are sometimes mistaken for mother and son; it always shocks me, but Steven finds it hilarious and teases me relentlessly.

I discovered he'd written a book, which he'd been working on for years, and I offered to look at it. I really didn't like it; it was enormously detailed, overly worked and lacked his energy, but I felt it had something, so I said to him, "You should write for children." His brain started whirring and he came up with The Wrong Pong. It was terrific and it reflected his humour and his wonderful, inventive language, so I was thrilled.

He then helped me a good deal with my work, too. I'm known for Horrid Henry and I started thinking I wouldn't be able to write anything else. I came up with an idea about a modern England without Christianity but I was too terrified to start writing. Steven asked me to mail him the first paragraph as his birthday present and I thought, I can write one paragraph. And from that I was able to write the book.

We both like to walk a lot, so we're always meeting for an amble – though I'm exceptionally clumsy: I've walked into a lamp-post twice today. And I just think, "Why of all people do I have to be with Mr Graceful all the time?"

Steven Butler, 28

A stage actor and children's author, Butler has appeared in productions from 'Peter Pan' to 'Horrid Henry'. He lives in London

I'd been cast to play the lead in a stage production of Horrid Henry and during rehearsals it was announced that the writer was coming to watch. It was hugely scary: I was still learning lines and harboured this dream of being a writer.

She came along for opening night and bought everybody a drink after, and we were all touched by how complimentary she was towards the play. Our group took her out clubbing the next night to a dive bar, as a thank-you, and she danced the night away with the rest of us; there was nothing mumsy about her, which I loved.

I'm quite an old man inside, passionate about good food and a homebody; she's young at heart, and we met in the middle.

I started going to Francesca's and cooking meals with her. We are opposites in the kitchen – and life. She is so organised, she has to follow recipes precisely. We'll be cooking a meal and she'll realise she might not have the right herb for a recipe and I'm like, "It's fine, throw something else in." She gets cold sweats over it and I tease her terribly.

She caught on to the fact I was passionate about books, so when she asked, "Do you write?" I told her about a book I'd been working on for years, and was terrified when she asked to see it. In my naivety, I expected her to say, "Oh my god, this is a literary masterpiece, don't change a word." So it was really tough to hear her say the opposite.

I'm considered eccentric in the Kent village where I grew up, so I made a joke to her, saying I think I must have been swapped at birth by trolls, and I saw her jolt and she said, "That's your book!" So I rolled with it; I'm now on book three.

The real shift in friendship was the first time I repaid the favour: she said, "I've written something new, will you read it?" It was nerve-racking for me. I wanted to say it was really good, but any first draft has too many descriptive sentences. I remember thinking, "Oh my god, I'm offering advice to Francesca Simon."

We're often out and about together, and I have to say her sense of direction is the worst I've come across; she could get lost in her own home. I've got used to gently shoving her in the right direction. We'll be talking and I'll interject, saying "Mind that step" or "300 yards and we'll be turning left." I feel like a TomTom.

It feels like such a natural friendship so it's odd when we get strange reactions. Some people imagine there's something dirty going on, which is a shock, as I just see her as a very funny lady.

'The Wrong Pong' (Puffin, £5.99) by Steven Butler is out on 5 May