Rosen was born in Cornwall. She studied psychology at Oxford before moving back to the West Country.
She now lives on the south coast of Devon with two imaginary cats, fantasising about getting a real one.
Readers have downloaded over 200,000 copies of Rosen's books. Several titles have broken into the Amazon charts, including a number 1 humorous fiction bestseller.
Having a celebrity in the family can be challenging, especially when your sister's famous for being a missing child.
The disappearance of Millie Jones has dominated the news for eight years, ever since the mediagenic toddler was snatched from a department store at Christmas time.
Certain that Millie is alive, her mother puts family life on hold to fight for the search to continue.
However, this Christmas things are changing. A shocking development causes the police to reopen the investigation and a new hope dawns.