JK Rowling has estimated that she has turned down more than 1,500 offers for Harry Potter spin-off projects in the last 10 years.

Speaking at the opening gala of Harry Potter And The Cursed Child in the West End, the author said finally agreeing to go ahead with a stage show had been a "daunting" prospect.

She said: "I think I've had probably three offers a week for the past decade to do either a musical or a play or an ice show or an opera - you name it, I've been asked to do it." She said meeting producer Sonia Freedman - whose credits include The Book Of Mormon and Funny Girl - convinced her that "this is the one".

Rowling also said she was delighted that fans who had seen the show during an eight-week preview run had avoided leaking details of the plot online.
She said: "They've been amazing, they've been incredible. It is the most extraordinary fandom so I'm kind of not surprised they didn't want to spoil it for each other but I'm so happy we got here without ruining it."

Rowling added she was excited to see the play again as it had been a long time since she walked a red carpet at a Harry Potter premiere, and revealed she hopes the play will travel as widely as possible.

Set 19 years after the events of the seventh and final book, The Cursed Child brings back Harry Potter, now grown up and an employee at the Ministry of Magic.

Harry and his wife Ginny Weasley wave off their youngest son Albus Severus to their old wizarding school, Hogwarts - but once there, Albus struggles with the weight of his family legacy and goes to extreme lengths to right the wrongs of the past.

The two-part play lasts five hours and was co-devised by Rowling, written by Jack Thorne and directed by John Tiffany.

The play's script will be released at midnight, allowing fans around the world to catch up on the latest instalment in the series.