Although it hasn't really caused the same type of furor that recent casting announcements have caused, it has actually been revealed that Scarlett Johansson will be replacing Samantha Morton in Spike Jonze's 'Her'.
The film's story and plot details have largely been kept under wraps, and all we really know is that it focuses on a man [played by Joaquin Phoenix] who falls in love 'with his Siri-like operating system'.
Jonze has confirmed that Johansson has replaced Morton for the role of 'the seductive voice of the operating system'. Jonze spoke about the casting change, explaining, "Samantha was with us on set and was amazing. It was only in post-production, when we started editing, that we realized that what the character/movie needed was different from what Samantha and I had created together. So we recast and since then Scarlett has taken over that role."
Others in the cast include Amy Adams and Rooney Mara, and the film will be distributed by Warner Brothers. Jonze has also repeated how close he is to Morton and how much he hopes to work with her in the future, so clearly the casting decision was smooth and amicable.