Entertainment

Rock bottom!

SISTER CRUSHIN’: Malin Akerman’s as Constance Sack, left, gets close with Tom Cruise’s Stacee Jaxx in “Rock of Ages.” (AP)

What can you say about a musical whose highlights include Tom Cruise belting out “I Want To Know What Love Is’’ directly into Malin Akerman’s butt? And a cringe-worthy Alec Baldwin and Russell Brand dueting on “Can’t Fight This Feeling’’ before sucking each others’ faces?

Don’t say you weren’t warned.

Adam Shankman’s campy and interminable adaptation of the long-running Broadway musical “Rock of Ages’’ tries to do for Los Angeles’ notorious 1980s rock scene what the film version of “The Best Little Whorehouse in Texas’’ did for the sex industry: rendering its seamy milieu fit for family consumption.

“Detroit Rock City’’ it ain’t.

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Even with Cruise more or less impersonating hip-thrusting, heavy-metal god Axl Rose in a padded supporting role, there isn’t anything approaching actual sex in this PG-13 musical, much less even a reference to any mood-altering substance stronger than scotch. There’s plenty of rock, though: a parade of ’80s rock anthems, too, many of them delivered by the terminally bland young leads, Julianne Hough (“Burlesque’’) and Diego Boneta.

Within minutes of landing on a well-scrubbed version of the 1987 Sunset Strip, aspiring singer Sherrie Christian (Hough) is taken in hand by Drew (Boneta), an aspiring singer who gets her a job at the Bourbon Room, where he works as a bartender.

The aging hippie owner (Baldwin) and his aide-de-camp (Brand, most of whose role seems to have ended up on the cutting-room floor) hope to save the place with a one-night stand by Cruise’s Stacee Jaxx, a jaded sybarite making a final appearance with his long-suffering band before going solo.

The major addition to the stage show is a subplot involving the wife of the secretly kinky mayor (Bryan Cranston), who wants to shut down Stacee and the Bourbon. This does provide an opportunity for Catherine Zeta-Jones, as the wife, to deliver the movie’s best number, “Hit Me With Your Best Shot.’’

Similarly, Mary J. Bilge’s subplot, set at a family-friendly strip club where Sherrie takes refuge after a lover’s tiff with Drew, seems little more than an elaborate pretext for Blige’s two numbers.

When Cruise isn’t singing into her (clothed) butt, Akerman plays a Rolling Stone reporter whose interview with Jaxx consists primarily of lecturing him that he’s been led astray by his oily manager (a hammy but amusing Paul Giamatti).

I don’t mean to suggest that “Rock of Ages’’ isn’t lacking in cheesy charms, particularly for fans of the big hair of the era (on men and women) and eyeball-gougingly ugly costumes. (Pretty much all of the women except Zeta-Jones dress like hookers.)

But with a couple of exceptions, I thought Shankman’s staging of the numbers — especially the leaden choreography and hackneyed locations such as the Hollywood sign — was far sloppier and less creative than for his last musical, the vastly superior “Hairspray.’’

When Drew joins a boy band, the opportunity to have fun with that phenomenon is largely squandered . The director also fails to impose any kind of uniform tone — Cruise, in an even more narcissistic variation on the self-help guru he played in “Magnolia,’’ in particular, seems to be acting in a different movie.

One reason I liked “Rock of Ages’’ — this plodding mess may help put to rest Hollywood’s inexplicable two-decade love affair with the awful ’80s, a pop- culture decade that’s overdue for a break.