The Oscar nominee joins incoming composer Nicholas Hooper, who will create the score for "Harry Potter and the Order of the Phoenix," the fifth film adaptation of author J.K. Rowling's epic series, according to a statement released Wednesday by Warner Bros.
Directed by Hooper's longtime collaborator David Yates, the movie also includes newcomers Imelda Staunton as frumpy Dolores Umbridge and Evanna Lynch as Luna "Loony" Lovegood.
Daniel Radcliffe, Rupert Grint and Emma Watson return as teen wizards Harry Potter, Ron Weasley and Hermione Granger.
"It's going to be a really cool cast," said Carter's publicist Jay Waterman.
Carter's film credits include 2005's "Charlie and the Chocolate Factory" and 1997's "The Wings of the Dove," for which she received a best actress Oscar nomination.