Whether as River Tam in Joss Whedons cult classic series and follow-up film, Firefly and Serenity, or as the indestructible android-from-the-future Cameron in Terminator: The Sarah Connor Chronicles, Glau has cornered the market on playing attractive, demure young females with the controlled homicidal power to destroy an opposing legion of trained warriors.

So it was only natural that as her first-ever animated voiceover role, Glau would fit neatly into the role of an uber-powered Kryptonian who falls under the spell of one of Supermans greatest foes. Glau finds the perfect mix of youthful curiosity, teen angst and alien-turned-Earth-girl aggression as the voice of Kara, cousin of Superman (and ultimately destined to become Supergirl) in Superman/Batman: Apocalypse, the ninth entry in the popular, ongoing series of DC Universe Animated Original PG-13 Movies arriving today, September 28 from Warner Home Video.

Based on the DC Comics series/graphic novel Superman/Batman: Supergirl by Jeph Loeb, Michael Turner & Peter Steigerwald, Superman/Batman: Apocalypse is produced by animation legend Bruce Timm and directed by Lauren Montgomery (Justice League: Crisis on Two Earths) from a script by Academy Award-nominated screenwriter Tab Murphy (Gorillas in the Mist). Produced by Warner Premiere, DC Entertainment and Warner Bros. Animation, Superman/Batman: Apocalypse is now available as a Blu-ray Combo Pack, Special Edition DVD, On Demand and for Download.

Glaus career has been populated with frequent visits to the fanboy realm, adding regular roles on The 4400 and Dollhouse to her featured gigs on Firefly/Serenity and Terminator: The Sarah Connor Chronicles. The professionally trained ballerina had a seven-episode run on The Unit, and will appear in the upcoming NBC series, The Cape, as well as in the film Knights of Badassdom.

Following her recording session, Glau freely discussed a number of subjects from the acting strengths of the Whedon alumni association to her consistent on-set nerves to a strong desire to land more adult roles. Heres how that conversation went

QUESTION: Was it easy to find a way to relate to Kara?

SUMMER GLAU: Kara was a really comfortable fit for me because she’s sort of a girl coming into her own. A girl becoming a woman and finding out who she is, and so I felt like there were moments when it reminded me of River because she is so powerful, but also young and nave and a little bit lost. She has this underlying strength that comes from out of nowhere.

QUESTION: Whats special about voicing Supergirl?

SUMMER GLAU: I think everything about being Supergirl is special. When I saw the graphics for her, I thought I don’t think I’m ever gonna look that good again, so I’m going to soak it up and enjoy it. I feel like animated characters always have longer calves than they have thighs. They have these tiny little thighs and these big, wonderful calves and then these big hips, and this tiny little waist. I feel like it’d be hard to keep your balance, but it looks good. Plus I loved this script, and I loved the character. Who wouldn’t love to be Supergirl? So I had a great time.

QUESTION: As this was your first foray in voiceover for an animated character, what did you have in your head while you were recording to stay focused on your character?

SUMMER GLAU: Ive found that I do my best when I’m not afraid of being embarrassed in front of everyone. You have to just go there in your imagination. I tried to picture everything around me, seeing these other characters, and then I just put it out there and hoped that you all didn’t laugh at me. And you might have because I couldn’t hear you (she laughs) , but I just went for it.

QUESTION: Without any spoilers, do you have a favorite scene or a favorite line in the film?

SUMMER GLAU: I love that first scene when Superman comes to rescue Kara and she’s putting on this completely different persona. Playing that change was really fun. And I also really loved when Kara meets the Kents. I thought that was really funny.

As an actress, it’s very gratifying to have a character that has such a strong arc, so that you can do so many different things in one script with one character. She starts out speaking a different language and being very scared and not relating to anybody, and then realizing that she’s reconnected with a family member. Then she goes to school and learns how to hone her skills. She just goes through so many changes good, evil, scared, confidant and that variety in one script is fun to play.

QUESTION: You did have an added degree of difficulty for your first voiceover session speaking Kryptonian. How easy or difficult was that task?

SUMMER GLAU: I still don’t know how that all turned out. It’s kind of a blur right now. I’m trying to remember what we actually ended up with because we tried a lot of different things. You can make it up because not many people know Kryptonian, so I don’t know exactly what I ended up saying. I am surprised that I’m not still working on my Kryptonian lines right now. I thought I was going to be doing the Kryptonian for a few hours (she laughs).

QUESTION: Youve played a lot of strong, powerful, quiet women. Are there similarities to Summer Glaus real-life persona?

SUMMER GLAU: Well, as far as my actual fighting abilities, I haven’t tried it out in real life. I don’t know what would happen. I did learn how to do some martial arts, but I can’t throw cars. I can’t bend metal like Cameron, and, I dont know if I’m as psychic as River. I’m definitely not as powerful as Supergirl but, you know, here I just have to use my imagination.

I was always very shy growing up, and I wasn’t really good at expressing myself in real life. And I don’t know why it is but when I’m playing someone else, it’s a really therapeutic thing for me. Being an actress has really opened up a lot of opportunity for me to see different sides of who I am. I think I’m still pretty shy in real life, but I just have to let go of that when I’m playing these characters. There were moments when I felt really scared to just let it out today, but it felt so good.

QUESTION: DC Universe films have been populated with Whedon alums. What is it about Joss Whedons actors that makes them so good with this material as well?

SUMMER GLAU: One thing that I recognized about the Firefly cast is that that group of people loves what they do and there’s an innocence and an excitement about just diving into a character and being part of this make-believe world. Some actors, I think, don’t like doing such fantastical characters. You have to just dive in and have that open heart to play these characters that are bigger than life, And that’s what Joss’ actors do pretty well.

I think that Joss writes characters that are so specific and rich and complicated. We had an ensemble cast for Firefly. It was a very big cast and we had to share story lines between a lot of people. But I felt like each person was so distinct that you found ways to relate to each. Joss does that so well. He has a way of writing characters that really fills them out and, as an actress, reading the material, you just lock into it right away. It’s so specific. It’s very inspiring.

QUESTION: So how did you find your very first voiceover/animation experience?

SUMMER GLAU: I’m very relieved today that everybody was nice to me at the end. I was very scared. I’ve never done any kind of straight voiceover work before. I’ve never done anything animated. I wasnt sure what the process was going to be. So I was worried about how I would do, but everyone was very accepting and I felt like it was a really creative environment. I felt very safe.

I felt a lot of freedom about trying different thing, and we got to try a lot of different things. And it surprised me that we were able to jump in and out of the scenes so easily, and I felt like I could stay focused. It helped me a lot to get the coaching and get ideas. And I was surprised that it went by so fast, too. We got through a whole script in a few hours. Amazing.

QUESTION: When was the last time you were this nervous on a set?

SUMMER GLAU: I was nervous this morning. But I get nervous every take. Every take, I feel butterflies. It never gets to the point where I feel like it’s easy. Not that it feels like I can’t do it, but there’s this thing about acting I feel like a little bit of magic always has to happen because you have to kind of leave yourself. You have to leave your reality and I think that it takes a little bit of magic to do that.

QUESTION: Why did it take so long for you to voice an animated character?

SUMMER GLAU: I never thought about doing animation before and this was the first time that anybody asked me to do it. I couldn’t think of an animated character that I would like to do more. Supergirl is amazing.

QUESTION: So youd like to do more?

SUMMER GLAU: Yes, please. More. (she giggles)

QUESTION: Do you stay mostly in the science fiction genre by choice?

SUMMER GLAU: I’m not going to question it because it’s been fantastic doing so much sci-fi. I think that maybe the reason why I have been able to do a lot of sci-fi is because I think that fans of science fiction are very loyal and they’re very nurturing and dedicated. They like to see their actors in other projects and they’ll follow you and support you and I think that’s why I’ve moved from one sci-fi job to the next. I’ve really enjoyed it. I think that science fiction gives actors some of the best opportunities thats where you find some of the most challenging, well written roles in TV and film.

QUESTION: Its obvious that you respect your fans. Do you have any unique fan experiences or antidotes?

SUMMER GLAU: I always keep my fan experiences very, very close to my heart. My favorite Comic-Con memory is the first one because I had no idea there’s no way to picture what it’s going to be like until you’re there. And being one of Joss’ actors is really special, because it’s like being part of a special family. Comic-Con was just beyond what I could’ve imagined. It’s an amazing experience for you to say thank you in person to the people that make it possible for you to do what you love.

I feel that our fans are so positive and so loving that I like to hear what they have to say. On Terminator, one thing that our cast liked to do was read if the fans noticed little things that we would put into the show. It became sort of a game. We loved to hear what they had to say and what they noticed or what they didn’t notice or if they liked choices that we made. It’s like a little love letter. You send it out and then you see what they say and it happens every week. I think they’re very thoughtful and so smart and, ultimately, we do it for them, so it’s great to hear what they think.

QUESTION: If you could wish for your next role, what would you want to play?

SUMMER GLAU: I think what I’m focusing on the most right now is just growing as an actress, and really being around actors that push me to be better. I’d like to grow and as I grow up, I’d like to play more adult roles. I’d like to play a woman. I’ve played a lot of girls and teenagers, but I’m not a teenager anymore. So I’d like to try to push myself in that direction. I want to keep doing TV; I love to do film; I should try to do comedy, even though I’m terrified of trying to be funny. I’ve always wanted to do a western and Id love to do a period film. Besides that, I just want to keep pushing myself.