Is it possible to be gaga for Gaga but not her movie? If we’re talking the third remake of “A Star is Born,” the answer is an unequivocal yes.

As an aspiring chanteuse improbably swept off her feet by a shaggy, drunken rock star, Lady Gaga more than holds her own in a role previously reserved for Hollywood luminaries Barbra Streisand, Judy Garland and Janet Gaynor. She sings, she acts and she strikes more sparks opposite Bradley Cooper than you have a right to expect. But too often her multi-talented skills are underserved by a leading man more preoccupied by pulling quadruple duty as director, producer, co-writer (with Will Fetters and Eric Roth) and star.

By spreading himself thin, Cooper obviously overlooks a potential jackpot in a co-star eager to prove she’s not just another poker face. Despite those restraints, she’s ultimately his savior, displaying enough moxie and heart to engage, even when the movie fails to match the hype coming out of the Venice and Toronto film festivals. It’s good, but not to the point of being more than the sum of its vague, discombobulated parts. But how do you flesh it out when it already feels butt-achingly long at 135 minutes?

Some of that impatience might be due to my binging on all the incarnations of “A Star is Born”; watching them play out exactly the same way every time. Cooper’s version is no different, containing zero surprises. Except, that is, for Gaga, who floored me, not just with her powerful voice and magnetic presence, but her underlying humanity, drawing on your empathy for a character giddy over her skyrocketing fame and disheartened by her famous lover’s sudden fall under the influence of alcohol and changing audience tastes.

You also love the unconventionality of her Ally’s beauty, “funny” schnoz and all. It’s exactly what attracts Cooper’s Jackson Maine, a long-haired, heavily bearded boozehound who — with dozens of post-concert watering holes to choose from — stumbles into hers, a drag bar where Ally has the distinction of being the only female singer. Just one verse of her seductive take on “La Vie en Rose” and he’s hooked. So are we; thoroughly won over by Ally’s winning blend of naivety and world wariness.

They meet backstage, where he sensuously removes her fake eyebrow fashioned out of electrical tape. But it’s she who is actually pulling back the layers on a jaded star who’s seen and done everything but fall in love. Their meeting fills the first 30 minutes, and it’s exquisite in both its adorableness and its subtle messages about the perks and pitfalls of celebrity. For every private jet, there’s a lack of privacy. Jackson can’t even walk into an all-night grocery without the checkout snapping a photo like she’s bagging big game in Africa.

Ally asks, “Does that bother you?” Yes, but it’s something you get used to, he tells her. Plus, he needs all the fans he can hold onto, as tinnitus is rapidly robbing him of his sense of hearing. It’s a race as to what will fail him first: His ears or his liver. Both are in grave danger when Ally’s head says, “No,” but her heart says, “Yes,” to a man who sees salvation in her purity of soul and talent. Then the film’s most pulsating moment arrives, as Jackson invites a hesitant Ally to join him on stage to sing a duet (the sure-to-be Oscar-winning “Shallow”) they wrote the previous night in a Safeway parking lot.

Cooper keeps the camera tight on Ally’s face backstage, as it slowly transforms from deer in the headlights to a sudden determination to seize her shot at stardom in front of thousands, sidling up to Jackson at the mic and belting out the lines in a way that sends shivers. It’s easily the quasi-musical’s crescendo; it’s also the start of a downhill slide for both Jackson and Cooper’s movie. Nothing ever comes close to matching that level of pleasure again — and there’s still more than an hour to go. By the third act, you feel like you’re watching an episode of “Nashville,” as romantic drama cedes to syrupy soap opera.

Enough with the negative; what about the assets, which “Star” has many? To start, the songs, most of them written by Gaga and Cooper, are instantly catchy, whether the genre is power pop or country rock. There’s also an underlying element of clinging to your principles in a soulless industry valuing spectacle over artistic integrity. Jackson continually reminds Ally of this, but is she listening? Apparently not, after falling prey to a sleazy Brit star-maker (Rafi Gavron) allegedly based on Simon Cowell. Queue the sinewy back-up dancers and a guest-spot on “SNL.”

That last nugget is a new element to the “A Star is Born” canon; so is the writing team’s interesting idea of giving our star-crossed lovers a semblance of family: A cranky, much-older half-brother (an ornery Sam Elliott) for Jackson; a gregarious, highly supportive dad (Andrew Dice Clay, very good) for Ally. Nothing much is made of these relationships (a few “Atta girls!” from the latter, a lot of long-brewing resentment between the former), but at least they’re trying. I also don’t quite get why Cooper decided to usurp Elliott’s gravely baritone for his voice, but it lends a smoky, hard-living quality to Jackson’s Eddie Vedder-like essence.

As a director, Cooper unashamedly allows his bias for actors show through via an overabundance of close-ups. It’s like Norma Desmond inhabited his soul. But the onstage stuff is well-mounted, making you feel you’re right in the spotlight with the performers. I also like the decision not to make Jackson a fall-down, bad-news drunk in the vein of Kris Kristofferson, James Mason and Fredric March in previous incarnations. Well, at least not until a moment at the Grammys that makes Kanye West’s rude interruption of Taylor Swift look polite.

As the movie steamrolls toward its inevitable downer ending, it grows clearer that slaving so reverently to the original 1937 film’s story by William Wellman and Robert Carson (inspired by Barbara Stanwyck’s marriage to fast-fading alcoholic actor Frank Fay) is troublesome in that by moving Ally and Jackson farther apart, our interest drifts right along with them. And that’s a killer, especially during an increasingly saggy second half.

Take heart “Alias” fans, there are a couple of fun cameos reuniting Cooper with former co-stars Greg Grunberg, popping up as Jackson’s chauffeur, and Ron Rifkin offering sage advice as a rehab sensei. But, sorry guys, there’s no Jennifer Garner, albeit Gaga is a fine substitute; every bit as strong, feisty and adept at punching guys out as Sydney Bristow. She’s also quite charming and affecting in her portrayal of an everywoman kissed by fame. So good in fact, you’d be right in saying, a star is born.

“A Star is Born”

Cast includes Bradley Cooper, Lady Gaga, Sam Elliott, Andrew Dice Clay, Dave Chappelle and Rafi Gavron.

(R for language throughout, some sexuality/nudity and substance abuse.)

Grade: B-