Actress Naomi Watts has signed on to star in the next Harry Potter movie, according to reports.

The pregnant Mulholland Drive star, 38--who will give birth in August--will play Draco Malfoy's wicked mother Narcissa in Harry Potter and the Half-Blood Prince, the sixth movie in the fantasy franchise.

The film is currently in pre-production but is expected to hit cinemas in November 2008.

The latest of the boy-wizard movies to be released, Harry Potter and the Order of the Phoenix, has already given Warner Bros. bosses their biggest opening ever, taking $561 million worldwide in its opening 12 days earlier this month.