The Harry Potter saga is set to continue, with the release of an eighth book containing the script for a new stage play telling the wizard's story on 31 July. The two-play – an original story by JK Rowling, Jack Thorne and John Tiffany – was first announced in December 2013, after the author said she had "received countless approaches" over the years "about turning Harry Potter into a theatrical production".

The story moves forward 19 years, after Harry was last seen in the final instalment of the books. Now a father himself, and an overworked employee of the Ministry of Magic, it's Harry who's waving his two eldest children off to Hogwarts. Harry Potter and the Cursed Child will tell the "untold part" of the boy wizard's background, including the story of the lives of his murdered parents, Rowling has said. Both The Boy Who Lived and his son, Albus, are said to struggle with their family's dark legacy.

David Shelley, chief executive of the publishers Little, Brown Book Group confirmed the news and said: "We are so thrilled to be publishing the script of Harry Potter and the Cursed Child. JK Rowling and her team have received a huge number of appeals from fans who can't be in London to see the play and who would like to read the play in book format – and so we are absolutely delighted to be able to make it available for them."

Rowling's best-selling, seven-volume Harry Potter series was published between 1997 and 2007 and has sold over 450 million copies worldwide. The "special rehearsal edition" hardback script book will be available from midnight on 31 July, a day after it makes its debut in London. The script's eBook will be published simultaneously.

Jamie Parker, currently starring in the West End show Guys and Dolls, will star as an adult Harry in the production. Noma Dumezweni, known for her 2006 Olivier Award-winning role in "A Raisin in the Sun", will play Hermione Granger, while London Road star, Paul Thornley will play Ron Weasley.

Previews of Harry Potter and the Cursed Child begin in May at London's Palace Theatre, with both plays set to open on 30 July. The stage play will run into 2017, which marks the 20th anniversary of the UK publication of the very first book, Harry Potter And The Philosopher's Stone

The news had the Hashtag #HarryPotter trending, as fans turned to Twitter to share their delight at the upcoming release of the new book.

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