Thanks to SkipMagic for closing my old thread. I’ll repeat this information and hope the report is more reliable than the bogus Naomi Watts rumour.
According to CBBC Newsround, Helen McCrory would seem to be Narcissa Malfoy, though it’s not yet up on her IMDB page or the IMDB HBP page. I know her mainly as Cherie Blair in The Queen. She was originally cast as Bellatrix, but had to drop out when she got pregnant, paving the way for Helena Bonham Carter. Now she gets to be Bellatrix’s sister.
If this casting changes, please read through the thread because this OP can’t be edited, and someone’s sure to post the most up-to-date info.
We should soon know who’ll be playing Lavender Brown and the young Tom Riddle.
There’s a trivial behind-the-scenes video (two videos in one) at YouTube. It shows the new Seeker outfit (looks like Ron does get his moment in the sun) and the 2nd bit (which starts out the same as the first) is about building Riddle’s orpahange.
Jim Broadbent is Horace Slughorn. Several scenes have already been filmed with him according to Veritaserum
Release date is November 21, 2008.