RTD has already said the special will not be the 1st part of DT's finale, but it will be closely linked and as we know it will be get a lot darker. In this special the Doctor will be joined by a new companion named Adelaide, who has been described as being the Doctor's most clever and strong minded companion yet.
Filming began on the 23rd February. Later in February, Tennant, Duncan and other actors were seen filming in Victoria Place, Newport. The filming took place on a city street, which was covered in artifical snow. On the same day a Robot with the word "GADGET" on it, and Ood Sigma, from Planet of the Ood, were seen. Could Ood Sigma be giving the Doctor his message- Your song will end soon?