The upcoming FX comedy Sex&Drugs&Rock&Roll may be written and created by Denis Leary, but his washed-up rocker dad character Johnny isn’t its only star. Instead, Johnny shares the spotlight with his fresh-faced aspiring singer daughter Gigi—played by Elizabeth Gillies, whose resume is far more impressive than her character’s. She landed her first commercial at age 12, made her Broadway debut at 15 (in the musical 13, alongside Ariana Grande), and starred on Nickelodeon’s Victorious for four seasons. All that experience has helped her face the challenges of singing live and improvising opposite Leary on the show, which follows Gigi as she attempts to kick off her music career with the help of Johnny and his former bandmates—a group that’s become somewhat of a dysfunctional family over the years.

Gillies talked to EW about her role, working with Leary, and making the leap from a Nickelodeon sitcom to a far raunchier comedy that’s rife with, well, sex and drugs and rock and roll.

ENTERTAINMENT WEEKLY: What was it like reading for the role?

ELIZABETH GILLIES: It was surreal for me to read. I saw so much of myself in the character, so I was over the moon and I had to get it no matter what. I’m glad I did. [Laughs] I went and tested with Denis, and we did a chemistry read in a screen test, and he had me do all the scenes in the pilot a bunch of different ways. We ended up improv-ing a ton, and I think that’s what did it.

Did you and Denis click instantly, doing all this improv?

We have really good chemistry together. We’re both ball busters, I guess [laughs]. We’re quick and we have similar minds. Going into the show, you have to be ready for anything. It’s a lot of improv. You can prepare, but you never know what’s going to happen when you get out there because Denis likes to switch things up a bit—which is really how I like to work, so it was fun for me.

You said you saw a lot of yourself in your character. What about Gigi made you want the role?

She’s a lot like me in a lot of ways. But you know, she has this hat of being the parental figure and of being the voice of reason, and she’s really the only one that’s clean and the only one that’s sober and the only one that’s really focused on the goal. She doesn’t have all the resentments that these guys have in the band, that have been going on for two decades. So while she’s trying to keep this all together, at the same time, she so desperately wants a family, a normal family. She wants her father and she wants her father to be okay. She’s also young, she’s 21, and she’s in a sea of people who are older than her, and she’s trying to juggle all of it.

Right, she has to juggle all of that and go up there and wow crowds with her singing.

That’s an extra little challenge on top of all that. Denis wanted me to sing live, which I love. He didn’t want it to feel like a lot of shows on TV, or most shows for technical reasons, where you record the song before and then you come on and you lip sync. He wanted it to feel really natural, so I sang live for, like, 90 percent of the songs, and I think that’s reflected well in the episodes. I think it makes the performances better, because I hate lip syncing, I’m not good at it.

It helps that everyone has to sing in the cast, or at least, perform.

It was like college. All of our dressing rooms were in a line next to each other, and we had a room where we would practice the music and you would hear us practicing… We were all so close. But we would all fight like we do on the show in real life, too. We would get into these, like, family arguments just like we do in the show. It’s funny. When you hang out with people long enough, you learn what buttons to push, and it’s a group that pushes buttons.

So who in the cast messes with you the most?

[John] Corbett, who plays Flash, is a huge prankster. I had told him I was afraid of elevators. It sounds crazy, but I was once stuck in an elevator so it’s not my favorite thing. I take elevators everywhere, but it’s not like my choice of transportation. So we’ll get in, and he’ll press the fire button and he’ll just jump in the elevator—stuff like that. I was like, ‘What are you doing? Why would you do this?!’ But it was fun. It was that kind of a crew.

How do you feel about leaving the world of Nickelodeon for this show?

I think that coming from Nickelodeon, people often have the misconception that making the move to adult TV is a big scary step that comes with inherent rebellion. This feels entirely natural to me. I don’t feel any of that. I’m playing a role where I get to sing, act, and be funny, and it’s just like a dream for me. As far as moving to more adult TV, I’ve always had a racier sense of humor and I’ve never played the good girl, so I don’t think it’ll shock any of my fans from Nickelodeon. They’re all grown up now anyways. [Laughs]

It didn’t feel like a dramatic transition for you, then?

No, it feels very natural to me. People always say, ‘Oh well, you don’t seem like a Nickelodeon kid,’ but I don’t even know what that means. I have a lot of friends from Nickelodeon, and I don’t know if we were ever ‘Nickelodeon kids.’ I was young. I did that show, I started when I was 15. I played the tough, kind of—for lack of a better word—bitchy kind of character. I was never the sweet girl or the main girl, where someone would be like, ‘Oh, this is so shocking and so terrible.’ My character on this show is actually sweeter than my character on Nickelodeon was. And I’m older, you know? I’m 21 now, and this is the totally natural thing for me. It doesn’t feel uncomfortable or weird in any way.