How We Met: Jill Murphy & Katharine Holabird

'You'd be surprised by how much self-doubt a writer can have. We try to encourage each other'

Stranger than fiction: Murphy (left) bumped into fellow writer Holabird while both were out walking their dogs © Elsa Quarsell

Jill Murphy, 58, is a children's author and illustrator. Her Worst Witch series was first published in 1974 and has sold over 3m copies. She lives in Cornwall with her teenage son Charlie

We met in 1990 when I was about eight months' pregnant. I'd been living in Cornwall, where my marriage had broken up acrimoniously, so I'd come to London to nest. I used to waddle up to Hampstead Heath every morning to take my dog for a walk. I was feeling really rough one day and sitting on a bench, wondering how I was going to cope. Riding round the corner on a bicycle came Katharine, looking shiny and healthy, with two bearded collies. She leapt off her bike and greeted me joyfully, and I asked her to sit with me so that the dogs could run around together.

I explained that I was living in a flat without a garden so I had to take the dog out, and Katharine asked if I had someone else who could do that for me. I ended up telling her all about my marriage breaking up and she was wonderfully sympathetic. Then she asked how I would look after myself and make a living. I told her I was a children's writer and she said, "Oh! So am I."

We were both slightly shy and anxious that we wouldn't know who the other was. In the end I bullied her into telling me what she had written. When she said Angelina Ballerina, it was a great relief and delight, as I'd bought her books for several children. Then I said I'd written The Worst Witch, which she had bought for her daughters.

We had a great chat and she said I must come to dinner. I pointed out where I lived and remember saying, "It's number five, five fingers, five gold rings," because I wanted so badly for her to remember.

Later on she put a note through the door asking me to dinner. I sat there with this note, waiting for Friday, when I could go to her house. When I did, her husband Michael came charging out from the kitchen – he recognised me from a dinner party in the 1980s. We'd sat next to one another and I remember him saying, "God, my wife would love you. You'd have so much to talk about."

Katharine and I became great friends; she looked after me and insisted I have a baby shower, which I thought was some American version of a baby bath. So I was surprised when I turned up to a garden party and everybody had brought presents.

When [my son] Charlie was about four and a half, I asked Katharine if she would be his guardian if I was ever run over by a truck. She said, "Where's the truck? We'll have him tomorrow!" It felt good to know he would be with someone so loving.

About four weeks later I found out I had breast cancer. It was wonderful to know that Katharine was there for Charlie. To me she is absolutely the Good Samaritan. I just thank goodness she's on the planet.

Katharine Holabird, 60, grew up in Chicago. She is the joint creator of children's character Angelina Ballerina; her books have been translated into over 20 languages. Katharine has three children and lives in London with her husband

I've lived in my neighbourhood since 1979 and have had a lot of pets over the years; and when you have dogs, you get to know the other dog-walkers who live near you.

One day I noticed this very pregnant woman with her dog who I had never seen before. I knew she was new to the neighbourhood, so I stopped to find out about her. Our dogs started chasing each other around and I said, "Our dogs are friends, so we should be friends."

We chatted and Jill's story came out about how she'd just moved to London under stressful circumstances. Then I asked her what she did. We were both amazed at the coincidence. I loved her from the beginning and invited her to dinner; we had so much fun together – she has the gift of the gab, a great sense of humour and can tickle anybody. I knew then that she'd always be my friend.

When Charlie was born, I was at the hospital with her. My children used to baby-sit him and he feels like part of my family. When Jill had a bad patch and was diagnosed with cancer, she asked whether Charlie could stay with me. He seamlessly went from her arms to mine and I took over as his extra mom.

Jill introduced me to Cornwall and I've spent a lot of holidays there now. I remember one time I went to stay with her, we rode a bike trail down to the sea, with Charlie on a little bike and the dogs running beside us. We stopped off at a pub for dinner and on the way back we cycled through the dark, singing and slightly tipsy. It was lovely.

We've had an ongoing dialogue about bringing up children and writing at home. It's so hard to be disciplined when there are children banging on the door, wanting to be fed. We both had very busy domestic lives but a piece of you has to be saved so there's enough energy to go into an imaginary world that you've created.

I think people would be surprised to know how much self-doubt a writer can have. Jill has always been encouraging to me and I've tried to be the same for her. Having a writing friend has made our relationship special, and I am really grateful we met in such a serendipitous way. She's someone I really treasure.

'The Worst Witch to the Rescue' by Jill Murphy (£9.99, Puffin) and 'Angelina Ballerina 25th Anniversary Edition' by Katharine Holabird (£6.99, Puffin) are both out now