On her 2010 don’t-call-me-Hannah-Montana album “Can’t Be Tamed,” Miley Cyrus covered Poison’s 1988 power ballad “Every Rose Has Its Thorn.” The rendition is a mess: a “Guitar Hero”-on-medium-difficulty solo, indiscriminate sprays of aural glitter, drums so compressed they sound like lasers. And yet, in such unholy ground, an auspicious seed was planted: Maybe Miley would sound good singing ’80s arena rock.

A decade and many, many stylistic detours later, Cyrus’s seventh album “Plastic Hearts” arrives at the same wise conclusion. Take one of its highlights: the stomping, wistful, acoustic-guitar-driven ballad “High,” which finds Cyrus sounding — in the very best way — like a hung-over hair-metal frontman suddenly unearthing a tender side. “Sometimes I stay up all night,” she sings, tapping into a rich vein of melancholy, “because you don’t ever talk to me in my dreams.”

Cyrus loves to embrace new genres, and she rarely announces these aesthetic pivots with subtlety. The Dolly Parton cameo and leather Nudie suit she sported on the cover made it known that “Younger Now” was her country album; the hip-hop influenced “Bangerz” showcased a cypher’s worth of rappers and Cyrus’s infamous grills; the Flaming Lips-assisted psychedelia of “Miley Cyrus & Her Dead Petz” began with the lyric, “Yeah, I smoke pot/Yeah, I like peace.” And so here comes “Plastic Hearts” with its cover shot by Mick Rock, the photographer known for his portraits of David Bowie, Iggy Pop and the Ramones. Mulletted and sneering out from her own high-contrast photo, the 28-year-old Cyrus all but screams, “Are you ready to rock?!”

But this is hardly just cosplay. (Though the greats know that rock stardom always involves at least a little cosplay.) “Plastic Hearts” is not a trendy rebranding of Cyrus so much as a convincing argument that she’s always been something of an old soul. Aside from her contemporary Dua Lipa, who shares the sleek and fun duet “Prisoner,” the elder guest stars on “Plastic Hearts” comprise an evocative ’80s-rock mood board: Joan Jett, Billy Idol and Stevie Nicks — plus Cyrus’s grizzled wail, which at times sounds like an amalgamation of all three of them.

Cyrus’s voice has always been a unique instrument: husky, a little froggy and — when a song calls for belting, like her great power ballad “Wrecking Ball” — surprisingly brawny. Even at 14, when she was cast on the Disney Channel series “Hannah Montana,” her voice seemed to carry a pathos beyond her years. As Cyrus has grown older and more comfortable experimenting with her gender presentation, she has seemed to revel in the inherent, freeing androgyny of her vocals. The buzzing low-end of “Plastic Hearts” allows her to play around with its guttural depths, and the industrial churn of “Gimme What I Want” provides the song her “Black Mirror” alter ego Ashley O dreamed of singing.

For all their power posing, though, these songs (all with writing credits for Cyrus) aren’t afraid of getting vulnerable. Written in the wake of her much-publicized 2019 split from her now ex-husband Liam Hemsworth, Cyrus occasionally indulges in winking, tabloid-baiting provocations (“Maybe gettin’ married just to cause a distraction,” she sings on the opener). But more often these songs are self-accepting declarations of imperfections (“But if you’re looking for stable, that’ll never be me/If you’re looking for faithful, that’ll never be me”). Or, as she puts it on “Bad Karma,” a snaking and absorbing duet with Joan Jett, “I’ve always picked a giver ’cause I’ve always been the taker.”

Two live covers that recently made the rounds online — and are affixed to the end of the album’s digital edition — reveal both the limitations and the startling power of Cyrus’s voice. Her muscular take on Blondie’s “Heart of Glass” unfortunately blows out the song’s nuance: Gone is the shrugging charm of Debbie Harry’s blasé falsetto, in favor of an all-caps, karaoke-esque assertion that Cyrus can really sing. Much better is her quaking, near-note-perfect performance of the Cranberries’ “Zombie,” which expresses such a reverent understanding of the song’s melodic leaps and emotional pull that one doesn’t even question what the former Hannah Montana is doing singing a ’90s alternative-rock classic about post-traumatic stress and decades of conflict in Northern Ireland.

But that probably hasn’t been a fair question for a while now. In those “Can’t Be Tamed” days when her post-Avril, transformatively wigged alter ego still grinned out from plastic lunchboxes, the last guardians of rock music’s supposed authenticity probably couldn’t think of a more obvious enemy than Cyrus. But, as she knowingly puts it on the album’s closer, a song that is far more thoughtful and understated than its title, “Golden G String,” suggests, “The old boys hold all the cards and they ain’t playin’ gin.”

After years of restless reinventions, it sounds like Cyrus has found a fitting context, and as a bonus, rock music has found its most earnest and high-profile millennial ambassador. Maybe rock’s not dead — it’s just in the capable hands of Miley Cyrus.

Miley Cyrus
“Plastic Hearts”
(RCA)