British author J. K. Rowling. - Photo by AP

NEW YORK: J.K. Rowling is back, and writing for adults. The author of the mega-selling ''Harry Potter'' series has an agreement with Little, Brown in the United States and Britain to publish her first novel for grownups.

The title, release date and details about the novel, long rumored, were not announced Thursday. Her seventh and final Potter story came out in 2007.

Rowling's Potter books, which broke sales records around the world, were published by Bloomsbury in Britain and Scholastic in the US.

Rowling will now share the same publisher with Stephenie Meyer, whose ''Twilight'' series at least partially filled the gap opened by the conclusion of the Potter stories.

''Although I've enjoyed writing it every bit as much, my next book will be very different to the Harry Potter series, which has been published so brilliantly by Bloomsbury and my other publishers around the world,'' Rowling said in a statement released by Little, Brown.

''The freedom to explore new territory is a gift that Harry's success has brought me, and with that new territory it seemed a logical progression to have a new publisher. I am delighted to have a second publishing home in Little, Brown, and a publishing team that will be a great partner in this new phase of my writing life.''

Any Rowling book would seem a guaranteed million seller, although it's questionable that her new novel will have the same mass appeal as Potter. Adult authors from E.B. White to Sherman Alexie have nicely managed the transition to writing for young people, but once a writer is defined as a children's author, the transition can be tricky.

Winnie the Pooh creator A.A. Milne, a successful playwright in his early years, once confessed that he was forced to say ''goodbye to all that'' after his beloved books about the bear and friends. Margaret Wise Brown, author of the classic ''Goodnight Moon,'' tried for years to write stories for The New Yorker.

But Rowling does begin with one advantage: The Potter books had an enormous following among readers of all ages, and she is widely credited with revealing to publishers that children's books were no longer just for the young.

Meyer's vampire novels and Suzanne Collins' ''Hunger Games'' trilogy also have caught on with both parents and their kids. Meyer herself wrote an adult book, ''The Host,'' a best-seller in 2008.