Now that Clara has officially debuted as Doctor Who's new companion, let's get down to solving the mystery of this "impossible girl." On Saturday's Doctor Who (8/7c, BBC America), present-day Clara (Jenna-Louise Coleman) will have her first outer space adventure in "The Rings of Akhaten." Coleman sat down with TVGuide.com to give the scoop on what it takes to play the Doctor's (Matt Smith) new companion, Clara's rivalry with the TARDIS and the highly anticipated 50th anniversary special: David Tennant and Billie Piper return for Doctor Who's 50th anniversary First of all, do I call you Jenna-Louise or just Jenna? Jenna-Louise Coleman: It's Jenna. I keep getting called Jenna-Louise [by reporters] but it's something that my mom calls me when she's angry with me. There is a huge mystery surrounding Clara: Two versions of her - one in the future and one the past - both died, and she is living in the present day. Has writer/executive producer Steven Moffat explained the mystery to you yet? Coleman: I only found out whilst reading the last episode of our season, which was a couple of months before we finished shooting. So I played most of the season not knowing, which is really good. I didn't need to know in order to play what I needed to do. Are you satisfied with how the mystery is explained? Coleman: It's being slowly teased throughout the series. It's like this slowly unfolding mystery, and we will eventually get payoff. Much is said about each new Doctor's signature style, but the companions also have their own sense of fashion. Does present-day Clara have any signature looks? What is her style? Coleman: I've got seven or eight girls I'm really close to, and I live with two or three of them in London. We all went to school together. I really wanted her to look like she could be any of them. So we've done loads of jewelry, which is featured throughout. I've got this "timey-wimey" watch actually, which has loads of different clock faces on it. Because of all the different Claras and all the dimensions, the costume drops some subliminal references. Clara is also quite collared actually and she's quite chic. I kind of liked the idea of that. She looks a little bit cutesy, but she's got biker boots on. She's the kind of girl who [sits] in a library reading, but she's actually quite a go-getter, action fighter with these little biker boots. She'll take you by surprise. She's not all that she seems. TV Scorecard: What's canceled? What's renewed? Moffat has said that one of the reasons why you were cast is that you could talk faster than Matt Smith. Are you naturally a fast talker? Coleman: I think it's to do with Steven's writing as well. It's kind of in the rhythm of it and it works for the pace, but I have a tendency to talk very fast anyway. Matt and I feed off of each other with it I think. But it causes problems because then I go to ADR [automated dialogue replacement] in the studio afterwards and I have to keep up with myself, which is quite difficult. You've got to look at your own face and match your mouth, so it's quite tricky when you talk as fast as I do. What's the chemistry between you and Matt behind the scenes? Coleman: It's great. The TARDIS is like our little home. As you're waiting for set-ups and things like that, we kind of just chill out in the TARDIS and gossip and chat. Your grandmother is a big fan of Doctor Who. Has she met Matt yet? Coleman: Not yet, but she will. She's going to come down to the 50th [anniversary special] while we're filming. She loves Matt. She wants to meet him. Does your grandmother have a favorite doctor, besides Matt Smith of course? Coleman: Yeah, she likes David [Tennant] and Matt. Speaking of the 50th, can you say anything about your involvement? Coleman: It's pretty exciting. We're shooting in 3-D. For me, it's a big celebration really. Without giving anything away, that's what the script is. It kind of pays tribute. It's a bit of a homage for the last 50 years, but it's very much about looking forward. It's just great to be involved in it. In a way, Clara is connected with the 50th anniversary. We saw in the Christmas episode that her birthday is Nov. 23, the same date that Doctor Who first aired. Coleman: In the Christmas episode, I didn't know why that was the case. But again, we will find out by the end of this series. But it's really exciting -- [the season finale] is phenomenal. My spine was tingling when I read it. Again, I'm teasing your so badly here, but there's the beginning opening sequence, which [is] kind of building up into the 50th. It's just huge. PHOTOS: TV boyfriends who ruin your real-life relationships Something that struck us about Doctor Who is that there's lots of running. Did you have to hone that skill as a companion? Coleman: Yeah, absolutely. It's funny because I've been doing period dramas for the last two years. You're in the corsets and you're quite still. You hit your mark and then you're there for the scene. Whereas this, it's so free in a way that being technical while remembering you're in small spaces with an entire crew, a guy on Steadicam and a camera operator. I get far into the running and get really exhilarated and try to sprint to all the poor camera operators. The technical side of doing something action is new for me. CGI and eyelines and all that -- there's a whole new technical side that I learned. And there's usually lots of expository dialogue while you're running... Coleman: Always. Also, when you know you're about to go for a take, there's like a Doctor Who stance, which is basically ready to fly off. So Matt and I both have this stance that we'd catch each other doing... getting into our action poses. Matt was a bit of a prankster with Karen Gillan (who played former companion Amy Pond) and vice versa. Is it the same with you? Coleman: He likes to tease me. He started off gentle. He was really, really polite and gentlemanly. Of course he still is, but now it's kind of like an older brother kind of thing. You can see he was kind of sussing me out really to find out which points he could tease me. He's quite a big wind-up. What was it like when you first stepped onto the TARDIS set? Coleman: It was strange because obviously it was a brand-new TARDIS, so it was a set that nobody's ever used before or seen before at this point. But this is where you're going to be for however many [of] the next couple of seasons or years, so it's like mine and Matt's new place. For him, he was running up and down all the stairs like a giddy kid who got his toy back. We didn't actually have the TARDIS for the first four months of me shooting because it was still being built. So it was pushed away in a dark corner and cordoned off so nobody could go in and look at it. You get to pilot that TARDIS in one episode. What does driving it entail? Coleman: There's a certain part of the TARDIS you go to, that liftoff thing. But you know, the TARDIS and Clara have a relationship. Actually I don't think we've talked about this in interviews before. It's something that's running through the series. Instead of it being like, "Does so-and-so like Clara?" The TARDIS and Clara have a bit of a face-off. So, the Doctor is obviously bringing back somebody new. I think we've done a whole additional content scene of me talking to the TARDIS, and the TARDIS is making fun of Clara. They kind of have an argument. They've got a relationship individual to the Doctor where they have a dialogue. TV characters more adorable than New Girl's Jess What happens in Saturday's episode, "The Rings of Akhaten"? This Clara finally goes to space! Coleman: Oh, I loved this episode. Yes, this is her first outer space experience. The Rings of Akhaten is this huge alien planet and there she gets lost and bumps into the Queen of Years. She's played by a young actress named Emilia Jones, who's about 10 years old and is one of the most phenomenal actresses I've ever worked with. So Clara makes this friend and helps her out, and the adventure goes on from there. Check out the trailer for "The Rings of Akhaten." Doctor Who airs Saturdays at 8/7c on BBC America.