Propelled onto the national stage in 2006 as runner-up on American Idol, Katharine McPhee launched not only a recording career but also series of television and film roles, most notably in the musical drama Smash.

Now, she’s taking on a new role, this time without any sort of musical accompaniment. On CBS’s new action/procedural Scorpion, from producer Alex Kurtzman (Sleepy Hollow) and creator Nick Santora (Prison Beak), McPhee plays Paige Dineen, an emotionally intuitive waitress and single mother who becomes entangled with the team of hyper-intelligent operatives -- headed by the brilliant but socially challenged Walter O’Brien (Elyes Gabel) -- contracted to contend with high-level national and global emergencies, providing the group with an unlikely but necessary down-to-earth human perspective.

Sitting down with Spinoff Online, McPhee discusses working without a musical net, finding the right tone to offer instruction to geniuses, and moving at 200 miles an hour while really standing still.

Spinoff Online: What got you excited about Scorpion when it first came to you?

Katharine McPhee: For me, it's exciting – it's something so different from what I did on Smash. I get to continue to just kind of develop as an actor. It's really what I love to do. I think I was really drawn to the character: I've never played a single, working mother with a kid who has lots of challenges, so that was different for me. I was also very much allured by the car scenes – the action scenes – and working with Justin Lin [the pilot episode director] because I just am fascinated by – when Elyes [Gabel] and I got to those scenes where we were in the car with green screen. And we were like, “How the heck are we supposed to do this and make this feel believable?” Because you're literally not moving – you're not going fast at all. You're not driving at 200 miles an hour, like they say. And sometimes as an actor, you can get into a debate with a director whether you agree on their note or not. And when it came to these action scenes, I completely surrendered. I was like, “Whatever you tell me to do I will do, because I have no idea what I'm doing.” So it was a really wonderful experience, and I got to get out of my comfort zone. And the director, Justin, he's really demanding, and I don't mean that in a negative way. I mean that like, he really expects, like, high quality from people in action scenes and from really tiny little scenes that may feel like little nothings. So he challenged me, and I got the part so last minute. So I was thrown into it. I was like a little discombobulated a bit for the first three days, and then once I clicked in, I clicked in.

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Tell me what's been the fun since the pilot as far as discovering who she is and what the show is?

Oh, gosh, well. I mean, I just have fun on set every day, so it's been fun since we've started really. I mean my first day, we were shooting – there's always challenges, too – but my first day of shooting, we were in Long Beach, and there was like a wind storm, basically, and my hair was like blowing everywhere. It was like my first scene where I actually had some lines, and I thought, “Well, this is interesting.” But I think just finding her voice has been the most interesting. It doesn't make sense for Paige – in the beginning, she's part of this new company but she's not a genius – to be rattling off statistics like the other geniuses, so there's been a lot of listening, to be honest, from Paige's perspective, and asking lots of questions. So for me, it's like I kind of get a lot more time than the other actors to really figure out what Paige's voice is. But I think more and more, she's just like the voice of reason and the voice of supporting humanity and what's the right thing to do versus the quickest thing to do. And she also is trying to help them with their behavior and their manners and silly things like that. What's been interesting for me is the dynamic of trying to play her like she's not being bossy, but she's been respectful but not bossy, but she's trying to get her point across. I was very cautious to not have Paige sound too whiny or too bossy.

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How are you doing laying down some potentially romantic notes between Paige and Walter, and finding the right tone to see how and if that's going to work?

I think you have to watch! I don't think it's going to be as romantically involved as quickly as people think it is, and I think if it does go in that direction, it will be not what people expect, and it will also be confusing to the audience because I think both characters will be confused about what it is – particularly from Walter's side. So I don't think anyone should expect too much as far as – we're not going for a full, just-letting-it-all-go-in-one-season kind of thing.

In what ways are you awkward or geeky, or feel like an outsider?

In any situation, you can say the wrong thing and like have people stare at you and go, “What?” And you have that moment where you're like, “Oh, this is what it feels like to not quite fit in.” Yeah, I mean, sometimes when I walk into like a large group of people, like an event or a party where you don't know anybody, you get that sense. These red carpets, I'm more used to them. I'm here to talk about something specific, so it's a little bit different than just being like, “Here I am: Miss Kat McPhee!”

Do you want more action sequences for Paige?

I would, yeah. We've had a lot of running in the first few episodes, and some bombs going off, but not quite as much action as the first.

There’s no musical aspect to this for you.

No, I know! It's remarkable!

You've been putting more and more emphasis on the acting. Is that what you want to do, or do you still look for musical outlets?

Oh, sure. I still have a record deal, and I've still been working on a record. And now, with the show coming out, there's very little time. So I don't know. I'm not complaining because I'm just grateful that I get to do – I never say I'm going to do one thing and do this thing. I'm very open to, like, whatever life has for me, as far as career goes. Yeah, I'm open to the possibilities of like, if I get a TV show and it goes to TV series, then that changes things, and I have to be open to that.

Scorpion premieres tonight at 9 ET/PT on CBS.