Billie Piper is back with a second season of the British series Secret Diary of a Call Girl (Sundays, 10:30 pm/ET, Showtime), in which Hannah — aka Belle, her working-girl alter ego — navigates a "real" relationship and encounters new women in her field. Piper, a former pop star, veteran of Jane Austen movies (Mansfield Park) and new mom, still treats her controversial role with wide-eyed curiosity. TVGuide.com spoke to her about her research into the world of prostitution, the overseas controversy surrounding the sexy show and which scene it was that made her feel "strange" to film.

TVGuide.com: What attracted you to this role?
Billie Piper: That it was so different from everything I'd ever done. And I think you have to keep trying new worlds, new experiences, and new characters. I'd done my fair share of sci-fi and period-drama girls. I was quite keen to play someone who was very different. And I loved the book; it made me laugh a lot. And I liked the idea of working with strictly female producers and writers; that was a big draw for me.

TVGuide.com: What surprised you the most in your research?
Piper: The "girlfriend experience": A man pays an escort to hold his hand and eat pizza with him; it's not necessarily just about sex. It's often men who just want someone to be with them, but not give them any grief.

TVGuide.com: Have there ever been any scenes that were more difficult to film than others?
Piper: In Season 1, the dominatrix stuff was... strange. It's mad to think that when you walk down the street in London, in small cubbies and houses and flats, and maybe even right next door, these things are actually happening. And they are the people who go and buy their coffee at the same place that you do. And that's their profession. That's what I find mad.

TVguide.com: Has this role changed your relationships with men?
Piper: I think it might if I was doing it for real. One thing I found quite fascinating [while researching the role] is that, not all the clients are raunchy, nasty, egotistical brutes. Some are really insecure and keen to know how women work sexually, or they have no self-confidence, or they can't get sex normally. That makes sense to me now, so I suppose I look at men who hire prostitutes differently.

TVGuide.com: Do you think the show advocates prostitution or women's empowerment? Or both?
Piper: I recently heard this thing on the radio about people wanting to open strip clubs in high-end shopping districts. There was this big debate, and one woman said, "Anybody who dances in a strip club is a victim." Well, I just don't believe that. Some people just see it as a means of making money, and it doesn't make them feel low. It's the same thing with prostitution. Who am I to say what you do is wrong, you're sick and you should be in jail?

TVGuide.com: How did the reactions to Secret Diary differ in the U.K. and the States?
Piper: In the U.K., the public liked it, but the critics did not. I think they were so used to seeing me play wholesome teenage girls or girls from Jane Austen novels, and suddenly I was taking all of my clothes off and simulating sex. In America, people were slightly more accepting, which surprised me. I suppose the Showtime audience is more open-minded.

TVGuide.com: Hannah/Belle wants it all: the sex and the money, but also the loving partner at home. Will she ever be able to have it all?
Piper: I don't think so. It's just impossible to have both, unless you found the most understanding man in the world. Life isn't really like that. It will be interesting to see whether she chooses her career over love.

TVGuide.com: Were any of the escorts that you met able to manage both?
Piper: One of them was. She had this guy who was understanding. In the end, they [became swingers]. So I suppose she really found gold there!