DAVID TENNANT - TENNANT TO STAY ON AS DOCTOR

David Tennant has denied rumours that he is to step down as Doctor Who at the end of the next series.

Comedienne Catherine Tate - set to join the show in 2008 as the Timelord's new companion - said in a radio interview that she believed the next series would be Tennant's last.

But speaking at the launch of the Christmas episode of the hit show, Tennant laughed off the speculation.

"Catherine Tate stitched me up good and proper," he said. "I started getting all these phone calls on Saturday lunchtime saying: 'Apparently you're leaving Doctor Who - Catherine Tate's just announced it on Radio 2'. Thanks Catherine!"

He told the BBC: "I said to her on Monday morning: 'Did you know you've caused a minor diplomatic incident?' She was completely oblivious that the phone had been ringing off the hook."

The Scottish actor confirmed he is to star in four Doctor Who specials in 2009 but had not been contacted about a new series in 2010.

"I'm doing four more specials and beyond that no one's asked me to make any decisions and I'm quite happy to be enigmatic for as long as possible," he said.

The Christmas Day episode, Voyage of the Damned, was screened before a celebrity audience at London's Science Museum yesterday.

Kylie Minogue stars as Astrid Peth, a waitress on the Titanic - and shares an onscreen kiss with the Doctor.

Doctor Who writer and executive producer Russell T Davies - who resurrected the show in 2005 - said the former Neighbours star was keen to return to acting.

"She did this because I think that's the way her thoughts are heading. She's missed it and fancied that discipline. I'd cast her again like that," he said.