Third hand report, but the best I can do...
My younger brother's school hosted Sir Ian last night. He was doing a talk about homophobia and fighting prejudice. During the question and answer session he was asked about playing Gandalf. He mentioned that he will be "flying back to New Zealand pretty soon" to play him again.
I'd like to assume he's referring to The Hobbit and not his own production of 'The Adventures of Gandalf and Alien', hitting cinemas some time next year.