David Tennant was a recent contributor to the BBC America special The Doctor's Revisted: The Fourth Doctor.
Speaking about the actor Tom Baker who took on the title role he said:
"I think the casting for Tom Baker, was one of those moments when the absolute right fit for something is found.
"He seems to have for free all of that kind of..madness. The kind of wild eyed, baffling sort of energy that just seemed to fit that character so well."
The Doctors Revisited continues with The Fifth Doctor on Sunday, May 26, 8:00pm ET/PT.
You can pre-prder The Doctor's Revisited Volume 1 on DVD here.
The DVD covers the William Hartnell, Patrick Troughton, Jon Pertwee and Tom Baker's eras, and includes contributions from David Tennant.
The Doctors Revisited includes a profile of each Doctor and one classic story for each, including: The Aztecs, Tomb of the Cyberman, Spearhead from Space, and Pyramids of Mars.