Since its debut in London in 1981, Andrew Lloyd Webber’s musical “Cats” has been staged continuously around the globe, seen by more than 81 million people in 50 countries and 19 languages. To that gigantic built-in fan base, the film version of “Cats” (Universal) will be nothing less than, well, catnip.

Viewers unfamiliar with the musical, however, may not purr so approvingly.

Based on “Old Possum’s Book of Practical Cats,” a 1939 collection of verse by poet T.S. Eliot, “Cats” chronicles one night in the life of anthropomorphized kitties named Jellicles as they ponder which of their ilk will be chosen to ascend to the “Heaviside Layer,” a kind of feline heaven (not to fear: religious overtones are nil).

Director Tom Hooper, who brought another smash-hit musical, “Les Miserables,” to the big screen, serves up a big, brash, over-the-top dance party worthy of Busby Berkeley. “Cats” is essentially a series of grand musical numbers stitched together by slender plot threads, and the choreography, running the gamut from ballet and tap to hip-hop, does not disappoint.

Costumes are another matter. Through the magic of computers, actors are transformed into cats of assorted breeds, colors and shapes, covered from head to toe in lifelike fur, and given ears that twitch and tails that wag. The effect is as impressive as it is unsettling and may disturb some viewers.

“Cats” takes place in the seedy underbelly of 1930s London, a place filled with “catsinos” and milk bars. Abandoned by her owner, a white cat named Victoria (played by ballerina Francesca Hayward) is adopted by the Jellicles, who have gathered for the aforesaid ceremony.

What follows is a succession of introductions (and songs), as Victoria, guided by the protective Munkustrap (Robbie Fairchild), meets the assemblage and learns their mellifluous names.

There’s Bustopher Jones (James Corden), an elite fat cat; the flirtatious and mischievous Bombalurina (Taylor Swift); Jennyanydots (Rebel Wilson), a large tabby cat who overindulges on mice and cockroaches; and Gus (Ian McKellen), short for “Asparagus,” a theater cat now past his prime.

Lurking in the shadows is the shabby Grizabella (Jennifer Hudson), who croons the film’s haunting signature tune, “Memory,” as she laments her lost status as the “glamour cat.”

Master criminal Macavity (Idris Elba) goes to extreme lengths to win the evening’s prize and ascend to the Heaviside Layer. That decision lies solely with the Jellicle matriarch, Old Deuteronomy (Judi Dench), who’s no pushover — even if, in her getup, she resembles the Cowardly Lion in “The Wizard of Oz.”

The film contains some rude humor and scary images. The Catholic News Service classification is A-II — adults and adolescents. The Motion Picture Association rating is PG — parental guidance suggested. Some material may not be suitable for children.

— Joseph McAleer