This is a really good interview, covering questions about each of the rest of the episodes this season, including [SPOILER ALERT]:
Q: What can you tell us about the finale?
SM: It’s full of surprises and questions that have never been answered in the history of Who, including the Doctors greatest secret. We’re not pretending, we’re not kidding, it’s actually going to happen. The episode is called The Name of the Doctor and involves our hero in a conflict that is very, very personal to him. Usually he’s saving other people, but this time he might be the one who needs to be saved. We’ll also find out what makes his new companion so impossible and there’s a surprise that no one has got right so far, and one that will change the course of Who forever!