Image copyright Getty Images Image caption JK Rowling's new film will be set 70 years before Harry Potter's story begins

JK Rowling has explained the meaning behind a cryptic tweet sent earlier this week, scotching hopes that it referred to a new Harry Potter story.

On Monday, the author posted the anagram: "Cry, foe! Run amok! Fa awry! My wand won't tolerate this nonsense."

Some fans translated it as: "Harry Returns! Won't say any details now! A week off! No comment."

But she later confirmed that it was really the first line from the synopsis for a film screenplay she is writing.

After one follower suggested "Newt Scamander only meant to stay in New York for a few hours", she replied: "YES!!!!!!!!!!!! People, we have a winner!"

Newt Scamander was the fictional author of a textbook on magical animals that featured in the Harry Potter novels.

Rowling herself released the book, titled Fantastic Beasts and Where to Find Them, in 2001 to raise money for Comic Relief.

Now, Scamander is going to be the main character in a film trilogy inspired by that textbook.

Rowling is currently working on the screenplay for the first film, which is expected to be set in 1920s New York after Scamander was commissioned to travel the world and compile a guide to magical beasts.

Rowling later tweeted that the anagram was "the first sentence of a synopsis of Newt's story", adding: "It isn't part of the script, but sets the scene."

She then wrote: "Newt only meant to stay in New York for a few hours. Circumstances ensured that he remained... for the length of a movie, anyway. X"

The first film is due to be released in 2016.

The author has previously said: "Although it will be set in the worldwide community of witches and wizards where I was so happy for 17 years, Fantastic Beasts and Where to Find Them is neither a prequel nor a sequel to the Harry Potter series, but an extension of the wizarding world.

"The laws and customs of the hidden magical society will be familiar to anyone who has read the Harry Potter books or seen the films, but Newt's story will start in New York, 70 years before Harry's gets underway."