There are only four Doctor Who specials to keep us amused this year, and so we’ve been desperately trying to find news for the first. All we know is that Lee Evans and Michelle Ryan feature, and they’ll be disappearing off to the Dubai deserts.

Now, before that one has even screened, we’re starting to get information about the second special. It was announced today that Lindsay Duncan will play the companion in the episode, and she will be “the Doctor’s cleverest and most strong-minded companion yet.”

Duncan, who is due to appear on our screens as Margaret Thatcher very soon, will play Adelaide, but little else is known about her. Of the role, Duncan says: “I’m thrilled to be involved in Doctor Who. I’ve never done anything like this before and I’m really looking forward to working with David Tennant and the Doctor Who team.”

The episode will go into production in the Spring to be shown on screens later in the year.