The collective star power and screen charisma of Nicole Kidman, Kathy Bates, Zac Efron and Joey King can’t pull the dull, unromantic and utterly predictible romanntic comedy “A Family Affair” out of the doldrums.

Scripted and directed by the usually reliable Oscar nominee Richard LaGravenese (“Behind the Candelabra,” “The Fisher King,” “Freedom Writers”), it pairs up Kidman as the mother of a Hollywood movie star’s assistant (King) with her daughter’s comically erratic, womanizer boss (Efron). And while King’s committed comical fireworks in reaction to this messiness lands a few exasperated laughs, the limited romantic chemistry of the leads and general humorlessness overwhelm the thin plot and everything else going on.

King is Zara, 24 and sentenced to do everything from script consulting to laundry, latte and kiss-this-latest-girlfriend-off gift work for Chris Cole (Efron), star of the Icarus Rush franchise, whose latest superheroics — “Icarus Rush 3” — are based on a script nobody likes, which scares him to death.

He’s a bit of a bully who promised her a path to “producer” duties and credits, but when we meet her, she’s stuck in traffic trying to deliver the diamond earrings he uses to break up with a woman as a prologue to him berating her for not getting there fast enough.

“I want a water and a LETTER of apology!”

That’s his thing. That, and telling her again and again that she’s fired, almost fired or about to get fired.

Efron has a little more luck finding a grin in the whole “I’m a movie star” shtick than he does in the bullying boss business. And it’s cute that LaGravenese named him “Chris,” like Chris Hemsworth, Chris Evans and Chris Pine.

Yes, he turned down an Oscar winning role as as blind alcoholic — “My eyes are too pretty to not be on camera.” And he has a lot of overhead to fret over — private jet, security, staff, etc.

Zara’s mom is a wealthy magazine essayist and fiction writer and a widow with a seaside Malibu villa, Audi EV and writer’s block. Her mother in law/editor (Bates) is pleased that she might be finally coming out of that, if not out of her mourning for her long-dead husband.

Zara’s “I quit/You’re fired” hissy over the childish Chris Cole’s latest unreasonable demands sets up a visit by Chris to their house, where he meets her perfectly-preserved mother and takes a tumble for her.

Zara is anxious to get her aspiring playwright pal Stella (Sherry Cola from “Joy Ride”) the rewrite assignment for “Icarus Rush 3,” which will open the door for Stella’s indie “coming of queer” coming of age comedy being filmed.

Zara’s got to translate the French director’s “notes” for thin-skinned Chris on the set. She doesn’t hold back.

And now she’s got her mother rediscovering her sexual needs with her rich and famous and mercurial boss.

“He’s a movie star. It’s not real” everybody agrees — including consults with mother in law Leila, even Zara’s bestie Eugenie (Liza Koshy). But nobody listens to anybody else’s concerns and on we go — Mom swooning, Chris making Big Gestures, Zara having meltdowns.

Hilarity does not ensue. The romance has its barely believable moments. Kidman summons up mature, sexy and beguiling, but has a harder time faking “smitten.” Efron’s self-aware “I’m famous” take on Chris doesn’t have anything beyond that which makes the character funny. Bates is motherly and barely in the picture.

That leaves it to King, a Netflix and streaming rom-com veteran (“The Kissing Booth” movies, “The In-Between,” etc.) to carry the picture. And if effort and amusing meltdowns alone could manage it, she’d have pulled it off. But even she finds making this work or at least play light and amusing a struggle.

The strain to find laughs shows, and not just in her performance. That’s deadly in a rom-com.

Rating: PG-13, sex, partial nudity, profanity

Cast: Nicole Kidman, Zac Efron, Joey King, Liza Koshy and Kathy Bates

Credits: Directed by Richard LaGravenese, scripted by Richard LaGravenese and Carrie Solomon. A Netflix release.

Running time: 1:51