Jk Rowling has said the stress of a case regarding plans for an unofficial reference book about the Harry Potter series has stopped her from working.
The authoress has filed a suit in New York City against Steve Vander Ark, a Harry Potter fan, and publisher RDR books for trying to publish the 'Harry Potter Lexicon', a 400-page reference book compiled from Vander Ark's website of the same name.
The 42-year-old told a Manhattan court on Monday that the pressure of the case had "decimated my creative work over the past month."
Though she cited her Britishness as a reason not to cry when asked about her connection to the character of teenage wizard Harry Potter, Rowling said the series of seven novels was "very personal" to her.
"I am an author - 17 years of my work is being exploited here. This is not about money," she was quoted by the Reuters news agency as saying.
In her US district court declaration filed in February, the 42-year-old expressed her frustration that "a former fan has tried to co-opt my work for financial gain".
And in a statement after her testimony on Monday she said the case "affects everyone and not just me."
"If books that plagiarise other works are permitted, authors, fans and readers stand to lose."
Though Rowling has supported unpublished fan-fiction, she argued in February that the publication of the 'Harry Potter Lexicon' could damage relations between authors and their fans, and cause authors to impose greater protection on their work.
An RDR statement on its website said at the time it was "determined to publish this book for the benefit of Harry Potter fans everywhere".
The publisher said it "believes Ms Rowling, who has championed the 'Lexicon' for years, will love reading the book just as much as she does the website on which it is based".
Rowling and the Harry Potter copyright-holder Warner Bros successfully delayed the publication of the book last year.