Donna Noble
This incarnation's companions include working class shop assistant Rose Tyler (Billie Piper), medical student Martha Jones (Freema Agyeman), and fiery temp worker Donna Noble (Catherine Tate). He eventually parts ways with them all by the end of the 2008 series finale, "Journey's End", after which he attempts to travel alone for the duration of the 2008–2010 specials before being accompanied by Donna's grandfather Wilfred Mott (Bernard Cribbins) on his final adventure in "The End of Time".