Naoko confirmed in a BBC Breakfast interview that the Toshiko Sato who appeared in an episode of Doctor Who and the Torchwood Toshiko are the same character.
Naoko: (On working on Torchwood) We kind of have a reputation for being pretty rowdy on set. We're pretty crazy on set. It's basically like Torchwood, because it's all-consuming. We're in the studio anything from between 10 to 14 hours a day. It's like a little pressure-cooker thing, and we just have such rapport.
Naoko: (On her favorite role) Oh gosh! It really is a hard one. I loved Ab Fab, it was an amazing experience and I was working with such funny people, I mean hysterical times because you're in a room with some very funny people and you're trying to make them laugh. The thing about comedy is that you mustn't try too hard otherwise it's not funny. I did an amazing drama / documentary about Hiroshima, about the atomic bombing, that's definitely up there as one of the most horrific experiences I've had and it kind of changed my view on life. That was amazing. And of course I'm loving Torchwood, so if I had to choose I couldn't choose!
Naoko: I pretty much love everything HBO make, from Sex and the City to The Sopranos, Six Feet Under and Curb Your Enthusiasm. And I also like documentaries, such as Long Way Down. I don't like those late-night interactive game shows, Live Roulette or whatever. I just don't understand it. I'd rather see reruns of old shows.