Former Holby City star Sarah Winman is among 11 first-time novelists tipped for success this year.
The 46-year-old, who played NHS boss Davina MacKenzie in the long-running medical drama, said she was "blessed" to be chosen from a longlist of 100 writers for her book When God Was A Rabbit.
Sarah joins novelists from as far afield as Sri Lanka, Latvia and Canada in the first ever Waterstone's 11 list.
She said: "I've always been writing but I've been an actress for 23 years and it is in the last five years I started writing novels.
"It is a book about a relationship between a brother and a sister. The book is in two parts, childhood and the secrets they forge, and adulthood and consequences of those secrets.
"Ultimately it is a family saga about what keeps families together and about being able to start again."
Sarah, who has also appeared in Silent Witness, Foyle's War, and The Forsythe Saga, said she had no plans to give up acting.
She said: "The writing came out of that. I was surrounded by scripts and I was surrounded by words. I still have an acting agent and think writing and acting can live side by side quite happily."
The 11 authors, whose novels will be published this year, were unveiled at an event at the bookseller's flagship store in Piccadilly, central London.
Extracts from their work will be published in a limited edition book by Waterstone's, before their novels are released fully.