History of Doctor Who the UK in the spring of 2007 and began airing in Canada and the US during the summer of that year. A 2007 Christmas Special "Voyage of the Damned" was broadcast on 25 December 2007 in the UK, featuring Kylie Minogue as a waitress named Astrid. The fourth series aired in the UK in 2008 featuring two companions; Donna Noble, who first appeared in "The Runaway Bride" and Martha Jones, who returned to the series for five episodes of series four. Billie Piper also returned to the show to reprise her original role as Rose Tyler. Following broadcast of the
Astrid Peth be the next companion after Martha Jones (played by Freema Agyeman) on 14 August 2007. Astrid's surname, Peth, was confirmed in the Christmas edition of "Radio Times". Davies has stated that the character was always going to be a "one-off" even before Minogue was cast and that Astrid would demonstrate "a whole new take – again – on what a companion can be". The name Astrid Peth generated some speculation before the episode's broadcast over the findings that "Astrid" is an anagram of "TARDIS", and that "Peth" means "thing" in Welsh. However, the episode established no such connection. On "Doctor