Joanna Lumley, left, and Jennifer Saunders bring Patsy and Edina to the big screen, but “Fabulous” doesn’t quite describe the movie. (David Appleby/Fox Searchlight Pictures)

You think millennials are resistant to growing up? Get a load of Edina Monsoon and Patsy Stone. The British fashion scenesters and kindred juvenile spirits are well past middle age, but they’re determined to hold on to the bad habits of their youth, partying all night and swilling champagne for breakfast — at least until the money dries up.

Jennifer Saunders, who plays Edina, created the characters for the BBC series “Absolutely Fabulous,” which debuted in 1992 and became a cult hit in the United States. Almost a quarter century later, she and Joanna Lumley, who plays Patsy, are still at it, as the continuation of their freewheeling story hits the big screen this weekend.

Those with no knowledge of Edina and Patsy should probably steer clear. “That was . . . weird,” one self-professed newbie said after a recent screening. “Though very British.”

Fans of the series, meanwhile, may have qualms of their own.

The good news is that a lot of the basic elements of the show remain intact. Patsy and Edina are still utterly self-absorbed and clueless. They badger Edina’s level-headed daughter, Saffron (Julia Sawalha), for being too serious, rolling their eyes and harrumphing dramatically anytime someone brings up social mores. They just want to have fun, dahlings!

On the small screen, their adventures were madcap and carefree. But the movie turns what was once antic into something closer to manic. With a throwaway plot and a parade of weird characters, the comedy tries to be bigger, bolder and more outrageous than the television series, but it ends up being a lot less funny. The most conspicuous change is that Lumley and Saunders used to look like they were having a good time, especially when the actors were on the verge of cracking up. But they don’t seem to be having as much fun this time around.

The story, thin as it is, centers on the disappearance of Kate Moss, whom Edina accidentally pushes into the Thames, where she’s presumed drowned. Rather than face manslaughter charges, she and Patsy steal away to Cannes with Saffron’s 13-year-old daughter, Lola (Indeyarna Donaldson-Holness). Running out of money, as usual, they decide to prey on an old tycoon to sustain their glitzy lifestyle.

All of this is really just an excuse for numerous pratfalls. Within the first few minutes, Edina and Patsy have tripped, fumbled or flailed a half dozen times. It’s tiresome, but not nearly as painful as the seemingly endless cameos. Saunders, who wrote the screenplay, apparently believes that the mere sight of Gwendoline Christie, Jerry Hall or Baby Spice is enough to send viewers into hysterics.

There are still some laughs, especially when Pats and Eddy, as they call each other, say and do what they’re best at: idiotically awful things. “I’m being trolleyed on Twitter,” Edina whines to Saffron, clearly more concerned about her own reputation than the fate of a supermodel she was hoping to use as a cash cow for her PR business. As for sight gags, Patsy’s bizarre morning ritual includes some good ones: Injecting her face with Botox is pretty tame compared with where the rest of her primping ritual takes us.

They’ll do whatever it takes to stay young — or at least to look like they used to. It would have been nice if the movie had done the same. Making the leap to the big screen hasn’t done Patsy and Edina — or their fans — any favors.

R. At area theaters. Contains strong language, including sexual references, and drug use.
86 minutes.