The fourth series of British science fiction television programme Doctor Who began on 25 December 2007 with the Christmas special "Voyage of the Damned". Following the special, a regular series of thirteen episodes aired, starting with "Partners in Crime" on 5 April 2008 and ending with "Journey's End". "Partners in Crime" marked the debut of Donna Noble, as played by Catherine Tate, as a full-time companion to the Tenth Doctor. A short Children in Need special was also produced. The series started production on 8 August 2007 and concluded on 29 March 2008. This was the final full series to star David Tennant as the Doctor, and the last with lead writer and showrunner Russell T Davies, however they would both stay until 2010, following a year's worth of specials.