Billie Piper has revealed she is undecided about whether to return as Rose in the next series of Doctor Who.

“I haven’t thought about it,” she told the BBC. “At some point you’ve just got to let go,” she adds.

Piper, who is pregnant with her first child with actor husband Laurence Fox, said that being a mum is more important than ‘the rest of my career’.

The actress has also denied suffering speech problems in recent Doctor Who episodes, blaming it on the cold weather while filming.

“It seemed fine when I heard it. When I went to work the next morning the make-up guy said, ‘Your speech sounded really funny.’ I wonder whether it was something in the final mix. Strange,” she said.

Billie Piper, 26, left Doctor Who after series two and told The Telegraph earlier this year that she had struggled to reacquaint herself with Rose’s accent before returning to the role.

“I had to watch a lot of the old stuff, so I could remember certain things about the character, because I’ve been playing posh birds since I left the programme,” she said.

“Rose is a bit of a chav, bless her. I needed to hear the voice and watch the posture and everything. But then the minute you get on set and you’ve got Russell T Davies’ scripts – he remembers how to write so well for Rose – you’re back there on day one, really. Well, I hope!”