A British law firm admitted Thursday that one of its partners accidentally let it slip that "Harry Potter" author J.K. Rowling had written a mystery novel, "The Cuckoo's Calling" under the pseudonym Robert Galbraith.
Law firm Russells said that one of its partners, Chris Gossage, had let the information slip to his wife's best friend, Judith Callegari -- the woman behind the tweet, according to the Associated Press. Her Twitter account has since been deleted.
Rowling is "very angry" for having her cover blown.
"I hoped to keep this secret a little longer," she wrote on her website. "[B]eing Robert Galbraith has been such a liberating experience! It has been wonderful to publish without hype or expectation and pure pleasure to get feedback from publishers and readers under a different name."
Rowling's response, according to the AP, was displeasure. "[O]nly a tiny number of people knew my pseudonym and it has not been pleasant to wonder for days how a woman whom I had never heard of prior to Sunday night could have found out something that many of my oldest friends did not know."
"To say that I am disappointed is an understatement," Rowling added. "I had assumed that I could expect total confidentiality from Russells, a reputable professional firm, and I feel very angry that my trust turned out to be misplaced."
The Sunday Times first broke the story over the weekend that Rowling was using a pen name. The newspaper said it had received a tip-off on Twitter which has since sent sales of the thriller skyrocketing.
The law firm said they "apologize unreservedly" to Rowling for leaking her secret.
