There have been rumours for some time about Peter Jackson (director of The Lord of the Rings movies and many more) directing Doctor Who. Jackson is well-known to be a life-long fan of Doctor Who and a couple years ago, it was confirmed that he was interested in directing the show—just so long as he received his own Dalek as payment.
Well, Peter Jackson has recently uploaded a video to his Facebook page, which many people are seeing as a confirmation that he is now officially directing an episode. The video certainly seems to imply that, although it never actually comes out and directly says as much. It's possible that he and Peter Capaldi (who appears in the video) are just having a bit of fun with the rumours. But it could well be a tease before an official announcement.
Assuming it is happening, I am very intrigued. I love The Lord of the Rings movies, but I'm much less enthralled by The Hobbit movies, so we'll have to see—but I suppose that's true of any situation. Nevertheless, I look forward to it.
Apparently, I can't embed a Facebook video without a Facebook account, so I'm embedding a copy someone else put up on Youtube. You can watch the original at this link if the Youtube one gets taken down.