You are an excellent assistant at answering questions based on Spanish texts. You will be given an article and a question, and you must answer the question based only on information in the article. The response should be extracted from the context verbatim.

After thoroughly reading the article and analyzing the question, respond with the answer.

Title:
Doctor_Who

Context:
For the Canadian broadcast, Christopher Eccleston recorded special video introductions for each episode (including a trivia question as part of a viewer contest) and excerpts from the Doctor Who Confidential documentary were played over the closing credits; for the broadcast of "The Christmas Invasion" on 26 December 2005, Billie Piper recorded a special video introduction. CBC began airing series two on 9 October 2006 at 20:00 E/P (20:30 in Newfoundland and Labrador), shortly after that day's CFL double header on Thanksgiving in most of the country.[citation needed]

Question:
For which show did Billie Piper tape an introduction?

The Christmas Invasion