Warren Beatty returns from a 15-year Hollywood hiatus with the delightful old-Hollywood drama “Rules Don’t Apply,” pulling triple duty as writer, director and star. And he’s playing no less than mysterious billionaire Howard Hughes.

After the contentious rise of Donald Trump, a movie about a demented businessman with delusions of grandeur may not whet the appetite. But “Rules” is not a biopic. It’s actually two movies in one; the first an unconventional love story about two people working for Hughes, and the other a farcical supposition of the mogul undergoing a softening of his rougher edges.

Taken as a whole, the movie — like its title — is an exception that doesn’t play by the rules. There is no message or explosions, no grand special effects; it exists purely for amusement.

And Beatty’s Tinseltown tale is a real charmer, buoyed by a terrific ensemble that includes the lovely Lily Collins (Phil’s daughter), the dashing Alden Ehrenreich (the new Han Solo), old-favorite Matthew Broderick, new “it” girl Hayley Bennett, and Beatty’s wife, Annette Bening. And the likes of Oliver Platt, Alec Baldwin, Ed Harris, Martin Sheen and Candace Bergen only add to the riches.

You’d think so much star power would be a slam dunk, but it’s likely to be a hard sell for filmgoers conditioned to expect stuff to happen on the hop. The film is a big wait. When the movie starts in 1964, reporters are waiting anxiously for Mr. Hughes, as he’s referred to in the movie, to telephone into a press conference, the purpose of which is to dispel a new book’s accusations that he’s gone off the deep end, lock, stock. Then the story flashes back “five years and four months” to the events leading up to that moment.

Like the reporters — and nearly every character in the film — we await the eccentric Hughes, who finally pops up after 25 minutes or so and always in the dark. He is quirky to say the least, with a tighter-than-tight inner circle, which Frank Forbes (Ehrenreich), a driver for Hughes, eventually cracks. Same for beauty queen Marla Mabrey (Collins), an ingenue who lands a contract at Hughes’s studio. Frank is assigned to drive the virgin from Virginia Marla and her overprotective mom (Bening) around Los Angeles. She’s one of 26 starlets (also Bennett and Megan Hilty) who has a car, driver, house and weekly paycheck courtesy of Mr. Hughes, the King of Hollywood. Drivers are instructed not to fraternize with the girls. So naturally, things heat up between Marla and Frank, who inconveniently has a fiancee back in Fresno. Marla turns out to be a naive Baptist amid a sea of buxom blondes. It’s a total cliched character, but Collins (“Mirror Mirror”) infuses it with a lot of pathos, as Marla chases her Hollywood dream in a land where things are not always what they seem. When Frank tells her she’s exceptional, that the “rules don’t apply” to her, Marla, a songwriter, sits at a piano and composes a titular love song that will later play a bigger part in the story. Collins, showing she’s her daddy’s daughter, sings it with sweet innocence. Don’t be surprised if the song receives an Oscar nomination.

Once the script pairs Frank and Broderick’s Levar Mathis together with Hughes, Beatty starts to reveal his character’s more twisted layers. He’s paranoid, an avid pilot, out to revolutionize the airline industry. He testifies before Congress. He eats TV dinners of steak and peas in the pitch-dark and takes phone calls in closets. You could hate him just for the way he objectifies women, going so far as to instruct his drivers to slow down over bumps so the young actresses’ breasts don’t bounce too much. Yet, Beatty earns empathy, playing Hughes with bumbling, quirky appeal in lighter moments and with a deep sadness when his long-simmering daddy issues come to light. As incorrigible as Hughes is, he’s also pretty funny, especially in a scene where Pratt, playing a Merrill Lynch executive, has an epic furniture-breaking meltdown because Hughes won’t meet with him.

Frank’s first encounter with Hughes takes place at 3 a.m on a dark pier. They chat, eat burgers, and when Hughes says: “Talk to my plane,” the camera pulls back to reveal the two dining at a table set under the nose of the mogul’s jet. It’s the beginning of an unconventional employer-employee relationship, one that Frank cultivates because he wants to pitch Hughes a real estate deal.

After stealing the show in the Coen brothers’ “Hail, Caesar” earlier this year, Ehrenreich (who looks like DiCaprio, who famously played Hughes in Martin Scorsese’s “The Aviator,” and acts even better) is at the precipice of superstardom. He’s not the least bit intimidated by Beatty when he goes one-on-one with the show business legend. On paper, nothing about this film should work, including the cheesy happy ending and the multitude of disposable characters. Yet Beatty, who hasn’t directed a film since 1998’s “Bulworth,” somehow makes it entertaining. Glad to have him back.

— Dana Barbuto may be reached at dbarbuto@ledger.com or follow her on Twitter @dbarbuto_Ledger.

“Rules Don’t Apply”

Cast: Alec Baldwin, Warren Beatty, Annette Bening, Haley Bennett, Candice Bergen, Matthew Broderick, Dabney Coleman, Lily Collins, Steve Coogan, Alden Ehrenreich, Taissa Farmiga, Ed Harris, Megan Hilty, Oliver Platt and Martin Sheen

(PG-13 for sexual material including brief strong language, thematic elements, and drug references)

Grade: B