Kelly Macdonald plays Helena Ravenclaw in Harry Potter and the Deathly Hallows: Part 2. That means she’ll likely appear in the film via flashback, since Helena Ravenclaw is super old or whatever. Macdonald, a native of Glasgow, Scotland, is best known for her roles in No Country for Old Men and Trainspotting.
A word from Kelly: “I was a nervous wreck for two or three months… I didn’t expect it to go anywhere afterward. I wanted it to but I thought I was still going to go to drama school after that.” (On winning a role in Trainspotting)