Saoirse Ronan confirms her role in The Hobbit. She mentions this in the latest issue of Total Film magazine. When asked how long it had been since she had known that she might be in it, she answers, definitely, at last: “When I did The Lovely Bones, they said, ‘We want you to be in The Hobbit’. I love the book. It’d be so cool to go back to New Zealand again.”
Of course, she doesn’t mention which role she will be essaying. Since the character Itaril has been mentioned in relationship to all the rumours of her being cast in the movies, we can assume that it would be this character.