J.K Rowling has written a biography of 'Harry Potter' character Celestina Warbeck

She told 'Today': "Celestina Warbeck is one of my favourite 'off-stage' characters in the Harry Potter series, and has been part of the Potter world ever since its inception.

"Although we never lay eyes on Celestina during the whole seven volumes of the Potter books, I always imagined her to resemble Shirley Bassey in both looks and style.

"I stole her first name from a friend with whom I worked, years ago, at Amnesty International's Headquarters in London; 'Celestina' was simply begging to be scooped up and attached to a glamorous witch."

The biography - which is available to read on the subscription-only site - details the establishment of a choir at wizarding school Hogwarts to cater for Celestina's talents.

She writes: "Celestina's extraordinary voice was apparent from an early age. Disappointed to learn that there was no such thing as a wizarding stage school, Mrs Warbeck reluctantly consented to her daughter's enrollment at Hogwarts, but subsequently bombarded the school with letters urging the creation of a choir,theatre club and dancing class to showcase her daughter's talents."

The passage follows on from the release of Rowling's short story earlier this year, which was told from the perspective of unscrupulous gossip columnist Rita Skeeter and featured Harry at 34 with "threads of silver" in his hair and a mysterious new scar on his cheek.

The 1,500 word piece entitled 'Dumbledore's Army Reunites' also featured well known characters Ginny Potter nee Weasley, Hermione Granger, Ron Weasley, Neville Longbottom, Luna Lovegood and Ginny and Harry's sons, James and Albus, as the group visit the Quidditch World Cup final.