Debuting in 1978 by Gerry Conway and Al Milgrom, DC Comics' Firestorm stands out from the superhero pack even now, nearly 40 years later, for having not one secret identity, but two: high-school student Ronnie Raymond and brilliant physicist Martin Stein. The two fused together as Firestorm, with Raymond in the nuclear-powered driver's seat and Stein as the voice inside his head.

Multiple Firestorm incarnations were subsequently introduced, but it's this classic take that serves as inspiration for the version on "The Flash," The CW's DC-based freshman hit series. Viewers have already seen Raymond -- played by Robbie Amell, cousin to "Arrow" star Stephen Amell -- who on the show is not a high school student, but an engineer, presumed dead following the particle accelerator explosion, leaving behind fiancee Caitlin Snow (Danielle Panabaker). "Alias," "Argo" and "Titanic" alum Victor Garber is slated to join the show in February as Martin Stein, with the two banding together to form Firestorm in his live-action adventures.

RELATED: Tom Cavanagh Talks Playing the Reverse-Flash, "Finally"

CBR News spoke with both Amell and Garber -- who previously worked together on a 2013 TV movie titled "The Hunters," based on the Joshua Williamson-written comic book "Mirror, Mirror" -- earlier this month at the Television Critics Association Winter Press Tour in Pasadena, talking the on-screen dynamic between Raymond and Stein, the real-life dynamic between Amell and Garber and the soon-to-debut Firestorm costume.

CBR News: Victor, Robbie, based on the TCA panel, it seems like there's definitely a fun dynamic between the two of you -- plus you've already worked together, so how exciting is it that things worked out this way?

Victor Garber: It's something that rarely happens. My affiliation with Greg Berlanti, and Marc and Andrew, that was the first thing. Then, they said, "Oh, we've cast Robbie Amell." That's like a gift.

Robbie Amell: It's a two-fer!

Garber: It's rare. It's great.

What has that familiarity lent so far to the unique relationship between Ronnie Raymond and Martin Stein?

Amell: We didn't have to get to know each other. Our first episode together, we're supposed to have been battling for control mentally against each other for over a year now, so there would be a familiarity -- and we already had that. We went out for dinner before we shot anything together, in Vancouver -- we saw each other at the table read, and went out to dinner that night, and got to catch back up. It was nice to come in knowing and having a friend, and having fun.

Garber: There's an immediate trust, that you can just throw the ball, and they'll bat it back. That's what acting mostly is. It's just listening and responding, and Robbie is really good at that.

Amell: What did you say? [Laughs]

Garber: It makes the whole process easier and more fun.

What's the dynamic like between the two characters? In the comics, there's usually a lot of banter back and forth, often to humorous effect -- how does it play out on the show?

Amell: We haven't gotten to do too many scenes like that yet, but from what we've shot, there's definitely a frustration with each other. We spend a lot [of time] in my head, battling for control. You spend a year that close to somebody, you need some time apart, so I think a little bit of the humor comes from us wanting nothing to do with each other, and being brought back together and having to team up to help out Flash. I'm really excited for future episodes, where we will get to have a little more fun together.

Garber: In my second episode, we come together knowing that we have a responsibility, and we both take that seriously. Frustration happens at first -- where I just say, "You're an idiot, I just want to get out of here" -- but then, as things progress, we realize that we have a responsibility, and we both accept that. From there on, of course, there will be banter and conflicts, which is what makes it fun.

Viewers haven't seen Martin Stein on screen yet. There's an idea of what the character might be like based on the comics, but Victor, what can you tell us about him on the show?

Garber: He is sort of a reluctant hero. He's somebody who came into this without meaning to, this conjoining experience, and then, when we are finally separated, he's sort of at a loss. He doesn't know quite who he is or what he is. I think it's a process of rediscovering his atoms, and finding himself again. He's a really smart guy who the Flash enlists for help. Barry comes to him, and they have a great meeting. I think he becomes sort of an advisor, mentor guy.

Robbie, we've seen the character of Ronnie Raymond already be two different things -- in the flashbacks, he has his life together, and then he's gone through a transformation and is definitely lost. Now it looks like he's moving to a third place, a more heroic area, as Firestorm. What's that been like for you, playing a character that in a short time, has had a wide range?

Amell: I got to have my introduction episode, with the flashbacks, quick scenes with Danielle -- all we really wanted to do was establish this relationship between the two of them, so people care when he gets killed trying to save her. The nice thing was, the producers let us have a little freedom with the lines, do our best to flirt and establish this connection on camera.

But most of my character so far has been this schizophrenic homeless guy, who's really nothing like Ronnie Raymond at all. The nice thing is, that character will soon be a thing of the past, and it's back to, like you said, a more heroic version of the first guy you saw. I like that he's a little goofier -- Danielle's character always says he's the only guy that can make her laugh. It's nice to play around with a character that's a little more lighthearted, even after going through all of this transformation.

Also on the panel, we saw the clearest view yet of the Firestorm costume.

Amell: It's got a lot of evolution to go through. It will definitely evolve. Right now, it just happens to be the wardrobe I was wearing when the splicer gets put on. The splicer is really the only piece of the costume that I think will be consistent, and that'll be a staple. I think the rest of it is interchangeable.

Garber: They're going to have more money next season, so they'll change it. [Laughs]

Sort of on that note -- obviously, both of these shows have been very successful for The CW, and there's acknowledged talks of further spinoffs. Firestorm has had his own comic several times in the past, has his own name value -- do you have any indication of a future life for the two of you together beyond "The Flash"?

Garber: Honestly, we really don't. Like Greg [Berlanti] was saying, there's a lot of talking going on, and I'm sure that we're part of that, but we're not privy to any of that.

Amell: They don't tell us crap. You guys will probably know before we do.

Garber: Really, I think all will be revealed at the same time, and it will come as a surprise to all of us.

Amell: I was the first person that told Stephen "Arrow" got picked up, because I happened to see it on Deadline. I called him, and he was like, "What are you talking about?" He had already booked it, they shot the pilot, but the announcement it got picked up, I saw it, I called him -- and then his phone started ringing. Sometimes it goes out to the trades before the closest people to it.

How soon will viewers see both of you together on "The Flash"?

Amell: You'll see us in February. The show comes back -- I think it airs five episodes straight without a break, and you'll see us a couple times in there. The episodes are really great for both of our characters, and our combined character. It's really a back story. One of them is called "The Nuclear Man," I believe.

The show is called "The Flash," but it's a strong ensemble. You both are now a part of it -- how much are you enjoying mixing up with the cast as a whole?

Garber: That's everything.

Amell: They've got great people.

Garber: That's the joy of being on a show: the ensemble.

Amell: When you're excited to go to work every day, you now you're working with special people.

"The Flash" returns with a new episode, "Return of the Rogues," tonight at 8 p.m. on The CW. Amell & Garber are slated to appear in February.