Billie Piper filmed so many energetic sex scenes for her latest role as a high-class hooker, she ended most days on set feeling sore and exhausted.

Secret Diary of a London Call Girl sees Billie play edgy escort Belle. And she now has first hand experience of how hard working in the sex trade must be.

She said: "It?s tiring filming sex scenes. Those days when you maybe have two sex scenes to do, you just want to be over and done with but they are vital to the piece."

Filming sex scenes with so many different actors was daunting for Billie, however, she soon got over her shyness.

"We?re telling the story of a hooker, you can?t be shy about the sex," she added.

"But there are two different kinds of sex scenes - the comedy sex, which is entertaining and funny and the emotional sex with regular clients like Ashok, who is someone that she cares about and could quite possibly be her boyfriend," she continued.

"Those are harder. I just had to get on with it and not be shy."
sections: Celebrities