The season finale of "Terminator: The Sarah Connor Chronicles" airs this Friday on FOX

The Terminator franchise is one of the most iconic in the entire science fiction genre, so one can imagine how the idea of actually portraying one of the cybernetic killers could make any actor nervous. Following in the footsteps of the Governator himself, Arnold Schwarzenegger, and Robert Patrick could be overwhelming for anyone, but the stars of "Terminator: The Sara Connor Chronicles" have found a way to make the parts their own.Actress Summer Glau plays Cameron, a Terminator sent back in time to protect John Connor. Glau was first noticed by the geek-world for her work on Joss Whedon's cult hit show "Firefly" and its film spin-off, "Serenity." She's also appeared on TV's "The 4400" and recently in a cameo as herself on CBS's "The Big Bang Theory." Shirley Manson is best known as the lead singer of the hugely popular alt-rock bad Garbage. She made the transition from singer to actress this year when she joined the cast of "Sarah Connor Chronicles," playing the role of Catherine Weaver, a powerful CEO who secretly happens to be a T-1001 liquid-metal Terminator. CBR News had the opportunity to speak with the two actresses at last month's WonderCon in San Francisco. They both spoke candidly about the finale of the season, the possibility of a third, and what it's like to play a Terminator.CBR: Summer, without giving anything away, can you tell us a little bit about what Cameron is going through in the season finale? Summer Glau: Well, I think at the beginning of the second season, the big thing in Cameron's life was that she was damaged. The chip was damaged and that threw her off her game. I think if my character was experiencing anything, it was insecurity about whether or not she was capable of doing her best at protecting John anymore. I think she was really struggling with the insecurity of a new girl in John's life, Riley. She was struggling with her dynamic, her place in the family and I think that's all going to come to ahead and in the finale there is just a huge slash change slash resolution.

Shirley Manson stars in "Terminator: The Sarah Connor Chronicles"

Shirley, in the finale, are we going to see a payoff to what has been set up with your character? Shirley Manson: Yeah. Absolutely, I can guarantee you that. There is an arc, and, you know, things shift really fast. So it's interesting, it's exciting and you'll be given some answers and some clarification as to what the hell this woman is up to. Summer, how have you been enjoying playing a Terminator on the series and were you worried at all when you agreed to take on such an iconic role?Glau: I think it's been the most fun that I've had in my career. It's been an amazingly complicated character. You know, in playing a robot, you'd think that it would be one specific thing but it's not, it's a combination of lots of different things. I've really been privileged to play a character that has evolved so aggressively throughout two seasons on TV and I hope I get a third season so I can keep going. It's just been incredible. I love my cast. Not everyone can say that they really feel like part of a team. They really care about a group effort and I'm really proud. The way that I've been approaching it, mainly and especially in the second season, I think that Cameron thought she understood herself. She thought that she had an agenda that hasn't been revealed and I think that when she was damaged, things were going on in her mind. She's learning a lot from the people around her but she also has to question herself because she has weaknesses now that she's struggling with. She has weaknesses so I think it's creating roadblocks in her goals. That's been a much more complicated thing to incorporate in my strategy of playing Cameron. But it's been really, really fun too. Shirley, when you were offered the part, were you aware that Weaver was a Terminator and was that intimidating at all for you to take on as an actress?Manson: I knew she was a Terminator but I didn't realize the part was going to be so big. I just thought I would be getting in a fight with somebody. I had no idea that it was going to be a recurring role at all. To be honest, when we were first shooting the episodes this season, the producers weren't sure where they were taking me. So I was working pretty much in the dark, which was difficult but in retrospect also helpful. If I had known how big the role was going to be, I would of collapsed. It would have been bad.

Summer Glau stars in "Terminator: The Sarah Connor Chronicles"

You mentioned that your character has an arc, is it difficult to show that when you're playing a robot that has no emotions?Manson: Day one, I spoke to [Executive Producer] Josh [Friedman] and said, "Well, who is she? Where does she go and what's her purpose?" He looked at me and was like, "I don't know? We're going to figure that out. You're on your own and you need to figure this out too." So I was a little out at sea but by episode five when they introduced the daughter it informed everything. To me, everything made sense. Okay, so she is a robot but she's already infiltrated society, she's a little weird but she's learning how to be more and more human as the season progresses and that really helped. But for me personally, what I loved about the Terminator movies is that there was always a bit of harshness on the part of the Terminators. You never looked at Robert Patrick and thought he was acting like a normal human. I mean, that was part of the fun to me. So I never wanted my character to be human, I wanted to bring a sort of silliness to her and that was a deliberate choice of mine. Whether you love it or hate it, that was my choice because I always got a kick out of Arnie and Robert Patrick. That's just part of the fun of it, cartoon-style. Your character has spent a lot of screen time with Ellison this season; can you talk about their relationship and working with Richard T. Jones?Manson: Well, there's a joke going around the set that we're going to have our own spin-off series called "Weaver and the Man" and it will be about a detective agency I run with Richard's character. We have great chemistry. We got along great. We spent so long laughing between takes it was embarrassing. He's a great guy and I felt that we did have chemistry on screen so I'm grateful for that too. He's lovely. I think he's a yummy man. He's a great actor and he really is amazing.Summer, how did the "Big Bang Theory" cameo come about and how is the "Summer Glau" you played on the show different from you in real life?Glau: It was different. You know, I was playing myself but I think I was trying to be funny. They tried to make me funny, which is why I wanted Josh to come be on set. I was nervous because it was supposed to be how people would react to me who knew my work as Cameron. So I was concerned about how people might perceive that. I was just honored to work with such talented actors. You know, I haven't watched every episode of that show, but I will tell you that I think that the actors on that show are some of the most brilliant young comedic actors on TV. So it was really interesting to see how they work because it is so different than doing a drama. It's completely different than being in a drama. From the very beginning, when they get their scripts to the very end. They just work in a way that is completely different. It's very delicate, the way they treat every line.

Shirley Manson stars as Catherine Weaver in "Terminator: The Sarah Connor Chronicles"

You know, when you do drama you try different things. Not my character, because I play a robot, but you come in and try to deliver from your gut. Something might happen in one take that you didn't expect, you just go with it and then your scene partner goes with it. But when you do comedy it is so precise. Every word can change whether it is funny or not. I didn't realize that. I had no idea. Every line that I would say, sometimes they would say, "Okay now do it going up, now do it going down. Say it quick and now say it slow." That's how specific it was to piece together the scenes. I laugh when I'm nervous so I was worried that I would ruin takes because I would laugh out of nervousness. But once we got started I was sweating bullets and I was not laughing. I was serious about doing a good job. You know what I love about the "Big Bang Theory" is? Those people, they really know their references. It's a smart group of people. They were referencing things that were over my head. It's not obvious. They're really very smart about the way they write things. But no, I would never act in real life the way I acted on that show. I was nervous. I said, "I feel like I'm being mean." They were like, "But it's funny." I enjoyed it a lot. What's harder for you to do, action or comedy?Glau: Comedy is definitely harder. Just give me a gun, let me run around and wrestle people. I'd choose that any day of the week. Finally, Shirley, since this was your first acting role, how do you think you've progressed as actress from the beginning of the season to now?Manson: I feel like I've learned so much over the course of the series. I've started to learn more about the process of acting and making a TV show. I've just started to learn how to develop a character. So I think that I'm more relaxed on set and I was so overwhelmed at first that I couldn't really function properly. It was so nerve racking. There was a learning curve. I think that it's the most extreme thing that I've ever done in my life. You rarely have to learn something in front of millions of people. It's very scary. I realized that I was opening myself up for a lot of criticism and I knew, myself, that my work wasn't perfect. So that's difficult in itself, to overcome your fear, your concern about what other people think of you and just push through it and try to do good work. So it was a real challenge.The season finale of "Terminator: The Sara Connor Chronicles" airs this Friday, April 10 on FOX.