The David Tennant Treat 4 Today is the Children In Need clip from 2005 which is the extra scene which David Tenannt and Billie Piper recorded to slip in between the end of Parting Of The Ways and the beginning of The Christmas Invasion.
However the person who uploaded this clip explained:
"This is the copy of the film as seen in the Region 2 DVD of the Complete Second Series, and it varies from the TV transmitted version (for some reason), that can be found on the Region 1 DVD and also the Complete First Series box set. It's fine, but the recap of "The Parting of the Ways" has changed, there is no cloister bell sound and the incidental music varies. I only own the Region 2 DVD...
This special short episode of Doctor Who was originally broadcast on 18th November 2005, for Children in Need. Also called "Born Again", the episode is the first outing (albeit small) for David Tennant as the Doctor, once again alongside Billie Piper as Rose, his companion. It seamlessly strings together the season finale and the upcoming Christmas special."