There are four specials planned. One for easter. One for Novemberish and then finally a two-parter Christmas special which will take place on the 25th December(Christmas day) and 1st January(New Years Day) so the doctor will become Matt Smith in the last episode which is new years day ready for series 5.
Well im not sure an exact date has actually been set yet, but david tennant is still signed up for three more "specials" so one can assume it'll be at the end of the third special towards the end of the year...
In actual fact, David Tennant is no long the tenth doctor... He is also the eleventh. I know he is still counted as only being the tenth, but the fact is, he's the eleventh. You see, at the end of 2008, during the episode Journey's End, the doctor regenerates. He become David Tennant again, but he has still regenerated all the same, and that makes 10 regenerations, meaning he became the eleventh doctor, right then and there. Still, this isn't really that important, as he didn't change person, and so remained being called the 10th.
I believe that the regeneration from David to Matt will be on 25th December 2009, during the Christmas special. This will leave Matt Smith perfectly, ready for his reign as the doctor in 2010, in season 5 of the new series.
In the fourth episode of the series i know this for a fact because there are only going to be 4 episodes in this series and hes going to be there for the whole 4 episodes, the new doctor is only in next years series.
I know for a fact that it will happen at the end of the fourth special, because david is signed to do three more specials, the waters of mars and the christmas two parter that will probably conclude on new years day.
I mean really is anyone in a rush to get rid of david?
there are now only 3 left:-the waters of mars witch is due any timenow and then there are 2 more witch is the 25th of december and 1st of january and on these days (25th of decmeber for defo) the amster and his wife lucy return but the master hasn't regenarated oh no hes the same but hwo well all will be reveled and in the waters of mars the doctor gets a chap at the door welll not really as in planet of teh dead at teh end teh old women (forgot her name) said to teh doctor"he will knock 4 times" an who else could tht be otherwise the master at first i thought it was the 11th dr telling the 10th to move on but thts impossible but now for defo its is the master soo we all ahve to sit tight and wait and find out what happens but bye bye david tennant and for all thoose who thought one of the two eposiodes were in november its not its in december and january!