J.K. Rowling has arrived at a Manhattan courthouse to testify about her lawsuit against a publisher.

Rowling says her copyrights are being violated by a fan who plans to publish a “Harry Potter” encyclopedia.

The showdown between Rowling and Steven Vander Ark is expected to last most of the week. Rowling brought the lawsuit against his publisher, RDR Books, to stop release of the “Harry Potter Lexicon.”

She’ll spend her breaks in the seclusion of a jury room _ away from any die-hard fans at the courthouse.