Tennant and Michelle Ryan get close in Doctor Who

After months of build-up, when David Tennant's Time Lord finally kissed Billie Piper's Rose, the show received record ratings.

But after Rose came Joan Redfern, played by Jessica Hynes; Astrid, played by Kylie Minogue and Martha, played by Freeman Agyeman.

And now ex-EastEnder Michelle Ryan can be added to the list.

Doctor Love: The Time Lord (David Tennant) gets close to Lady Christina de Souza (Michelle Ryan) in Planet Of The Dead, to be broadcast on BBC1 on Saturday

Face off: The Doctor looks less than impressed by his new love-interest

In this weekend's Easter special, Planet Of The Dead, Tennant and Ryan lock lips in a passionate scene.

Ryan, who made her name in EastEnders as Zoe Slater, plays Lady Christina de Souza and the show starts with her in a catsuit stealing something important.

She then tries to escape on a London bus.

Tennant said of the show: 'London transport being what it is, it slips through a wormhole in time and space and ends up on a planet on the other side of the universe.

The kissing Doctor: First came Billie (L), as Rose, then Kylie, as Astrid

'There's another alien race that are on the planet called the Tritovores and then there's also stuff going on back on Earth as well.'

The Doctor is trapped on the planet, but manages to use a passenger's mobile phone to communicate through a wormhole.

Tennant said the special was 'quite a romp'.

'It's got some dark moments. There's a tiny little hint at the very end that it's all about to get a lot darker.

'Because obviously at the end of the year it's the end of the line for the 10th doctor. This is kind of a romp. This is the last time the Doctor gets to have fun, in a way.'

In an interview with the Guardian, Ryan admitted she was in awe of Tennant.

But she flatly denied rumours that she once auditioned to replace Billie Piper as the doctor's assistant - a role that went to Freema Agyeman.

Denying the reports, she said: 'Not true. There are so many stories about me that aren't true.'

The show is the first of four special episodes in which Tennant will appear before handing over to his replacement, Matt Smith.

The Doctor Who Easter Special will be broadcast on BBC1 on Saturday.