Re: [RUMOUR] David Tennant & Catherine Tate signed up for Big Finish!
If true, it will be interesting to see what they come up with for the inevitable multi-Doctor specials to cross the 10th with his pre-Time War selves. If he is with Donna that he is still likely before "Day of the Doctor" so he would still not have helped 11 change his mind, even though all of him were involved.
A return of a 5th Doctor-10th Doctor mission? Or see 10's reaction to the 4th, 6th, 7th, or 8th Doctors. Or even the 1st, 2nd, or 3rd Doctors since they sometimes show up with voice impersonations.
Or Donna's reaction to meeting another Doctor.