Doctor Who has always been near and dear to David's heart, over the years he has had the opportunity to work with several previous Doctors.
Christopher Eccleston (9th Doctor) - 1996 movie "Jude"
Peter Davison (5th Doctor) - 2000 Mrs. Bradley Mysteries episode "Death at the Opera" and again in 2007 for Children in Need in "Time Crash"
Sylvester McCoy (7th Doctor) - 2001 Big Finish audio story "Colditz
Colin Baker (6th Doctor) - 2004 Big Finish audio story "Medicinal Purposes"