The popular children's author met Molly Field at Great Ormond Street Chlidren's Hospital shortly before she died. Despite having a brain tumour that affected her vision, Molly wrote novels called The Adventures of Ella Rose, which helped raise thousands of pounds for charity.
Jacqueline said: "I meet a lot of children with very distressing illnesses and only met Molly once but she made a deep impact. She was so sweet and funny. "I thought, 'What can I do to show Molly made a real impression on me?'"
Jacqueline knew Molly had a six year-old sister, Isabella, and, said: "I realised I'd been writing a book about sisters who quarrelled a lot but love each other very much. So I asked mum and dad how they'd feel about the dedication."
Her book The Worst Thing About My Sister is published on February 2.
The dedication reads: "In memory of Molly and her sister Isabella who loved each other dearly."
Jacqueline said: "The girls in my book have a very different relationship from Molly and Isabella, who were very close. This is an extra way of keeping her memory alive."
Molly was diagnosed with a brain tumour in March 2010 and died six months later. She wrote her trilogy while having treatment and was reading to classmates until a few weeks before her death.
The £5 books have helped raise £30,000 for Haven House Children's Hospice where Molly spent her last days. The family, including mother Mel and father Steve, also raised £3,000 for Great Ormond Street.
Her mum, Mel, 39, said: "She wasn't the type of child to get ill or moan. Writing was her passion and they are magical stories. She was a gorgeous little girl. Isabella now loves reading because of Molly and her books are in the school library. Jacqueline's one in a million."