Original Seventh Doctor

An incarnation of the Doctor was seen during the Fourth Doctor's mindbending contest with Morbius. (TV: The Brain of Morbius, AUDIO: Cold Fusion) According to one account this man was the Other, whom the First Doctor was a reincarnation. (PROSE: Lungbarrow)

behind the scenes
The face of this Doctor were first introduced in TV: The Brain of Morbius but it was not until AUDIO: Cold Fusion thirty years later, in 2016 thatthey were confirmed to be incarnations of the Doctor.

In TV: The Caves of Androzani (written by Holmes) the Fifth Doctor 's regeneration was very different from other incarnations. Before his death he says things like Is this death? and It feels different this time. Holmes also wrote Morbius (albeit under the name Robin Bland) and if one counts the 'Morbius' Doctors then the Fifth was the Doctor's last incarnation. The Fifth Doctor's final words suggest that even he thought he was dying, possibly due to the 'Morbius' Doctors coming before the First Doctor.