Promoting her new book, M Train, at Hearst Tower in New York on Monday (05Oct15), Smith revealed she has already started work on her next book.
She said, "I have my detective. I've been working on it for a few years at my own pace."
The Because the Night singer added, "I don't like the crime or the stress of crime, (but) I like the mind of the detective."
Fans should expect her literary hero to bear similarities to late author Henning Mankell's troubled Kurt Wallander, who she believes is one of the greatest detective characters.
Mankell lost his battle with cancer on Monday, aged 67.