Hand it to Warner Bros. for their approach to their favorite piece of Roald Dahl intellectual property.

They didn’t just remake “Charlie” or “Willy Wonka and the Chocolate Factory.” They took a stab at giving us a back story about how “magician, inventor and chocolatier” Willy got his start.

They spared almost no expense in acquiring a big name cast, new music (by Neil Hannon and Jody Talbot), choreographing big new production numbers with more sprawling production design, giving us something like the most spectacular “Wonka” ever.

They cannily hired the wit behind “Paddington” to direct and co-write it and make the chocolate trains run on time.

With Hugh Grant, Keegan Michael Key, Rowan Atkinson, Oscar winners Olivia Colman and Sally Hawkins on board, the only worry might have been Timothée Chalamet in the title role. And he gives the chocolatier a light, upbeat touch. There’s none of writer-Roald’s sinister, punishing edge in Young Willy.

And Chalamet can sing, showing off a lilting, pleasant movie musical (not Broadway ready) voice, holding his own in some pretty impressive dance numbers, and selling his chocolate with an off-center twist.

“Hover chocolates?” They not only let you fly, they’re “salted with the bittersweet tears of a Russian clown.”

“Wonka” is a musical comedy that bowls you over with bigness — big stars, big sets, big numbers and big whimsy in service of a story that takes Willy from a ship’s cook gig on a fanciful fantasy film freighter to an unnamed 1930s EuroCity where he does battle with the singing, dancing, back-stabbing “chocolate cartel” (Paterson Joseph, Mathew Banyton and Matt Lucas).

“The greedy beat the needy” is their motto, and the movie’s cautionary message.

Willy’s got his tiny chocolate factory in a traveling trunk, unusually delicious and large beans that he stole from Oompa Loompa land — which a lone Loompa (Grant) is hellbent on stealing back, in bean or Wonka Chocolate form.

All he has to do is escape an enslaving laundry run by villains played by Colman and Tom Davis, where young Noodle (Calah Lane) and Abacus Crunch (“Downton’s” own Jim Carter) are among those working off their debt. He’s got to dodge the chocolate-craving/ever-fattening-up chief of police (Key) and his minions and outfox the cartel.

All if he wants to manifest the “destiny” his late mother (Hawkins) urged him into.

The new music’s good, if forgettable, which is why “The Oompa Loompa” song and that “Pure Imagination” theme song from the ’60s songsmiths Leslie Bricusse and Anthony Newley are reprised and sampled here.

No, it doesn’t have much of Roald Dahl’s trademark darkness. But Dahl daftness? Sure.

I was never a huge fan of the Gene Wilder film that made “Willy” a pop culture touchstone. “Wonka,” for what its worth, drags and sags through its middle acts before freshening up for a big, long finale.

But all involved have managed to back-engineer a prequel into that “classic” original, and not embarass anybody in the process — save for Hugh Grant as “the little orange man” with green hair. And he’s in on the joke.

It’s light and fun and when all else fails, which it seldom does, the sheer scale of it all, that “bigness,” bowls you over and lets you and the kids leave the cinema with a big grin, and a big craving for chocolate before you get home.

Rating: PG (Some Violence|Mild Language|Thematic Elements)

Cast: Timothee Chalamet, Hugh Grant, Calah Lane, Keegan Michael Key, Paterson Joseph, Simon Farnaby, Matt Lucas, Sally Hawkins, Rowan Atkinson, Jim Carter and Olivia Colman.

Credits: Directed by Paul King, scripted by Simon Farnaby and Paul King. A Warner Bros. release.

Running time: 1:58