LONDON -- A black actress playing Hermione Granger? J.K. Rowling has no problem with that.

The bestselling author of the "Harry Potter" books has responded to mixed reactions after the cast for "Harry Potter and the Cursed Child" -- a new London play featuring Harry as an adult -- was announced Monday. The role of Hermione, made famous in the film versions by Emma Watson, will be played by Swaziland-born actress Noma Dumezweni.

Rowling said on Twitter that the character's skin colour had in fact never been specified in the books. "Canon: brown eyes, frizzy hair and very clever. White skin was never specified. Rowling loves black Hermione," she wrote, adding a kissing emoji at the end.

The play, based on a new story by Rowling and others, opens July 30.