Le Monde spoke to David Cronenberg & Don DeLillo and they mention Robert Pattinson.
Again I used Google to translate so take the translation loosely but I think you'll get the gist of it. (I hope ;-})
Why did you, as a director choose to adapt a novel?
David Cronenberg: First of all laziness, to write an original script can take years. Cosmopolis, that took me six days. A record for me. It was very strange. The first day, I transcribed the dialogues, in a direct format scenario. The following day, I added the details of the action. And that's all. I read, wondering if this was a movie. It was. With the structure of dialogues. Don DeLillo's dialogues are unique. They have a specific rhythm. They are totally realistic, but at the same time stylish.
The dialogues are crucial?
David Cronenberg: They're a key element of the scenario, the only really found on the screen. Everything else changes once in production. The dialogues give you an idea of the quality of the film. Are the characters are interesting? How do they interact?
This approach to the scenario may seem surprising from an author well versed in the genre of film?
David Cronenberg: We often think that cinema is a visual art. I personally think that this is a very complex alloy. For me, the essence of cinema is a face that speaks. That's what we film the most. I heard that the last twenty-two minutes of the film, where there is none other than Paul Giamatti and Robert Pattinson in a room, this is theater. I don't think so. In theater, you wouldn't have close-ups, no camera movement, no changes in light. This is the cinema. Without close-ups there is no cinema.
And Robert Pattinson?
Don DeLillo: The character he plays is very close to the one in the novel. I haven't seen the Twilight series, in which he acts, but I impressed my two 13 year old nieces, saying that Britain's Robert Pattinson would play in a film adapted from one of my books. They show me respect now! (Kate: I bet they do. Now is the time to suck up to Uncle Don)
David Cronenberg: Casting is an occult art. It is a matter of intuition. There are objective factors, though. The character is 28 years old, he is American. So you need someone who is that age, and that can have a perfect American accent. The film is a co-production between France and Canada. Also, I could use only one American actor, and for me it was Paul Giamatti. I could take a Briton, however.
Then of course there is the presence of the actor. He needs to be able to embody this character who is particularly complex, cruel, brutal, vulgar, in a sense, and very sophisticated and vulnerable at the same time, naive and childish? To make people believe that such a young person has achieved so much, takes strength and charisma. And he's in every scene. This doesn't mean he must be beautiful, but it must be pleasant to look at him for an hour and a half. (Kate: Oh believe me it's more than pleasant to look at Rob for an hour an a half ;-))
Finally, he must have a certain notoriety. Since the film costs a certain budget, you need to be able to excite your financial partners a little. (Kate: And I'm pretty sure that Rob excites financial partners (along with everyone else) more than a little.)
With all these constraints, the list of actors is relatively short. And I started thinking about Rob soon enough.