There will be a new companion in the second of four Doctor Who specials this year.

BBC announced today that acclaimed stage and screen actress Lindsay Duncan has been cast as Adelaide, companion to David Tennant’s Doctor in the yet to be titled second special of 2009.

Exec producer/writer Russell T. Davies commented:

“Lindsay is an incredibly talented actress and I’ve been an admirer of her work for some time. We are delighted to announce that she will be joining the team and playing the Doctor’s most strong-minded companion yet.”

This second Doctor Who special will go into production this spring. There’s no word yet whether Duncan is being considered for the role of companion to our next Doctor, Matt Smith, although it would make for quite an interesting age contrast – Duncan is 58, and Smith is 26.

Duncan TV resume includes HBO’s Rome and the upcoming BBC2 drama Margaret in which she portrays The Iron Lady herself, Margaret Thatcher.

So, what are your thoughts on this casting choice?