The estate of the late Adrian Jacobs on Wednesday added Rowling as a defendant in a lawsuit it filed in June against Bloomsbury Publishing PLC for alleged copyright infringement, according to a statement released by the estate's representatives, who are based in Australia.

The lawsuit, filed in a London court, claims Rowling's book “Harry Potter and the Goblet of Fire” copied substantial parts of Jacobs' 1987 book, “The Adventures of Willy the Wizard - No. 1 Livid Land.”

Jacobs' estate also claims that many other ideas from “Willy the Wizard” were copied into the “Harry Potter” books. Jacobs died in London in 1997.