The Sixth Doctor is an incarnation of the Doctor, the protagonist of the BBC science fiction television series Doctor Who. He is portrayed by Colin Baker. Although his televisual time on the series was comparatively brief and turbulent, Baker has continued as the Sixth Doctor in Big Finish's range of original Doctor Who audio adventures. Within the series' narrative, the Doctor is a centuries-old alien Time Lord from the planet Gallifrey who travels in time and space in the TARDIS, frequently with companions. At the end of life, the Doctor regenerates; as a result, the physical appearance and personality of the Doctor changes. Baker portrays the sixth such incarnation, an arrogant, flamboyant character in brightly coloured, mismatched clothes whose brash, often patronising personality set him apart from all his previous incarnations.