Here's the article from http://www.rte.ie:
Narcissa Malfoy cast in new Potter movie
The actress who will play Narcissa Malfoy in the sixth Harry Potter movie has been revealed.
CBBC Newsround says that Helen McCrory will play the sister of Bellatrix Lestrange (Helena Bonham Carter) in 'Harry Potter and the Half-Blood Prince'.
McCrory was originally cast as Bellatrix Lestrange in the fifth film but was unable to star because she was expecting a baby.'Harry Potter and the Half-Blood Prince' opens in cinemas on 21 November 2008.
Learn more about the upcoming film at http://www.imdb.com