Originally cast as Death Eater Bellatrix Lestrange in "Harry Potter and the Order of the Phoenix," Helen McCrory had to back out of her commitment to star due to pregnancy.

Luckily for "Harry Potter and the Half-Blood Prince" director David Yates, this time she's making an Unbreakable Vow.

According to the CBBC, McCrory has been cast as the haughty, domineering Narcissa Malfoy in the upcoming film (see "Harry Potter's Newest Teacher: Jim Broadbent To Play Horace Slughorn In 'Half-Blood Prince' "). A blond-haired, blue-eyed, pureblood witch, Narcissa is a fellow minion of Lord Voldemort along with her sister Bellatrix, her husband Lucius and her son Draco.

Since Narcissa only makes two appearances in the sixth Harry Potter novel, McCrory's casting almost certainly means that Yates has decided to film Narcissa's trip to visit Professor Snape at Spinner's End. One of the only three chapters in all seven novels not told from Harry's perspective, "Spinner's End" centers on Narcissa as she pleads with Snape to help her son, who is charged with killing Hogwarts Headmaster Albus Dumbledore on the orders of the Dark Lord. While there, Narcissa manages to convince Snape to make an Unbreakable Vow. The slippery Potions master magically promises to protect Draco in his quest and to finish the deed if he should be unable to.

Narcissa has a much more prominent, and crucial, role in the seventh book, "Harry Potter and the Deathly Hallows."

McCrory played Prime Minister Tony Blair's wife in last year's Oscar-winning "The Queen." She has also appeared in "The Count of Monte Cristo" and "Casanova." "Harry Potter and the Half-Blood Prince" is slated to open November 2008.

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