The majority of people know Juliette Lewis as an accomplished actress — she starred in Natural Born Killers among other films — but these days she wants to be recognized for another career — music.

With Lewis’ new album, Terra Incognita, the movie star has seemingly crossed the threshold from musician-wanabee into bona fide artist; she’s barely an actor now. At least that’s how she looks at it.

“Music has been my whole life,” she says on the phone from Philadelphia. “I hadn’t done a movie in four years until recently. I’m much more involved in my music.”

The change from screen siren to songwriter didn’t come over night — this is Lewis’ fourth record (and first without backing band The Licks), but only now does it actually appear as if she’s a real musician.

A big reason for that is her new sound. The frantic rockers, which always seemed a bit too thrown together, are gone. In their place are far more polished sounds. There are still plenty of distorted guitars and upbeat tracks, but there’s also Janis Joplin-like blues (Ghosts) and the David Bowie sounding Suicide Dive Bombers.

Lewis is well aware of the new musical direction; she says this album marks the first time she’s ever really paid attention to songwriting.

“My first agenda was all about the live show,” she explains. “But now I real feel like I’ve come into my own musically. I never cared if people knew me from my films, or if they thought they’d be seeing a joke. Whatever got them in the room and I’d give people a really exciting live show.

“When I came off the road I had a moment to reflect and say holy s*** I did it,” she continues. “I’m now good for more than a handful of tickets all over the world, so that means I can really lock in and make a record full of feeling, something more vulnerable than ever and people will still show up.”

There’s no doubt that Terra Incognita has more feeling. On the aggressive Fantasy Bar she lambastes Hollywood life; the title track sees her singing about a failed relationship. And while it’s still unclear just how this fresh direction will work for her, at least she tried something new.

“I really wanted to challenge myself,” she says. “Terra Incognita is a Latin phrase for unknown territory and that’s where I wanted to go musically, physically and emotionally. It’s a metaphor for the journey I am about to take.”

• Juliette Lewis and Band of Skulls play the Opera House Friday