She had a hit track with Step Back In Time - and now that's what Kylie Minogue appears to have done with the Doctor.

This first shot of the pop princess on the set of Doctor Who was taken two days ago.

Minogue, 39, crouches in fear next to the Timelord, played by David Tennant.

The singer has been cast as Astrid, a waitress on the Titanic, in the Christmas special.

The episode, Voyage Of The Damned, began filming in Cardiff this month.

The story follows on directly from the ending of the third series, when viewers saw the Titanic ship crash through the Tardis's walls.

Minogue has said: "It is an incredible thrill to be joining David and the entire Dr Who production for this year's Christmas special.

"Dr Who enjoys a unique history and it is going to be very exciting to be a part of that."

The episode was written by Doctor Who's executive producer and head writer Russell T Davies.

Sitcom actors Geoffrey Palmer and Clive Swift will also play lead roles in the Christmas episode.

Speaking at today's BBC1 autumn season launch, BBC1 controller Peter Fincham joked: "As we lose Neighbours we gain Kylie."

Neighbours is switching from BBC1 to channel Five after BBC bosses refused to pay the £300 million demanded by distributors to secure the Australian soap.

The fourth series of Doctor Who features comedienne Catherine Tate, best known for her catchphrase "am I bovvered?", as an assistant.

Freema Agyeman is also set to return when the new series goes out in spring next year - but she will only be one of two assistants.

Mr Fincham denied the BBC had been blinded by the allure of celebrity in recruiting Tate, saying: "That's absolutely editorial creative thinking.

"Doctor Who needs surprise. I would completely back and defend Russell's right to evolve and develop the series as he thinks editorially. It's purely an editorial thing.

"I think it's exciting. Doctor Who sets a high bar and you've got to keep jumping over it."

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