P is for... Peth, Astrid

Native of the planet Sto, Astrid was a waitress on a luxury spaceship which copied the Titanic. This was on a cruise to Earth's orbit at Christmas 2008. The Doctor befriended her after saving her from a bullying passenger. When the opportunity arose to join a shore party, the Doctor added her as his guest as she had told him that she had never set foot on an alien planet before. Arriving on a deserted street, empty except for a newspaper vendor named Wilf, they learned that people shunned London at this time of year due to previous alien activities.

The party was recalled to the Titanic as it was threatened by meteoroids. These crashed into it, causing the spacecraft to begin a slow descent to impact the Earth. Astrid helped the Doctor and surviving passengers get to a place of safety, their progress hampered by the Heavenly Host service robots which had been reprogrammed to kill. The whole disaster had been engineered by the ship's owner, Max Capricorn, in revenge for being ousted from his company. The Doctor discovered he was on board and went to confront him, but Astrid followed and discovered what was going on. The Doctor had been captured, but Astrid took to a forklift truck and used it to ram Capricorn's life support unit - pushing him into the ship's reactor. Unfortunately, Astrid fell with him.

The Doctor realised that her body print would still be in the teleport buffer and attempted to bring her back, but she only existed as a disembodied spirit. The Doctor allowed this to go free, so that she could travel the universe.

Played by: Kylie Minogue. Appearances: Voyage of the Damned (2007).

• After coming to fame internationally in Australian soap Neighbours, Minogue went on to have a successful music career. Her creative designer, Will Baker, was a huge Doctor Who fan, who had used the Cybermen as the basis for a set of backing dancers on the 2006 Homecoming tour. (This section of the show was titled "Dance of the Cybermen"). It was through Baker that approaches were made for her to guest on the series.

• Fan speculation prior to broadcast was that Kylie would play a personification of the TARDIS - Astrid being an anagram.