here is Astrid Peth played by Kylie Minogue in the xmas special "voyage of the damned". She has been coined/said to have been for this xmas special the doctors companion; sadly she didn't get to be a companion in the regular episodes.
15 Sci-Fi Movie Quotes That Make Great Pick-Up Lines - "You're going to steal ME! No, you HAVE stolen me. You ARE stealing me. Tenses ARE difficult, aren't they?" - Idris in Doctor Who, "The Doctor's Wife"