Fifty Shades of Grey casting news

Universal Pictures has just announced that Eloise Mumford (The River) has joined the cast of Fifty Shades of Grey. I haven't read the book, nor will I ever, however it looks as if she will play Kate Kavanagh, Anastasia Steele's best friend and roommate in the story.
Sounds like a lot of fun this Fifty Shades of Grey.
Just throwing this out there, but the people who will go see this film are probably the same audience who go and watch the Sex and The City or The Devil's Wears Prada. I am not apologizing for stereotyping because this is probably the truth.