The Spice Girls, who have been weaving their way through the Tri-State Area as part of their reunion tour, will take the stage Monday night at Madison Square Garden. Ticket holders can expect something along the lines of a fashion show with models who sing and dance.

Wacky costumes — platform sneakers, colorful boas, and patriotic leotards — have always been as important as (if not more important than) the music for the five-woman group. Fashion defined each girl’s stage persona. Victoria Beckham (“Posh Spice”) favored sleek tube dresses. Emma Bunton (“Baby Spice”) wore girlish, pastel designs and pigtails.

During the girl-band’s chart-topping heyday in the mid-1990s, there was no unifying theme to the styling — underscoring its message of individuality. But this time around, the reunited band has a more cohesive and (ever so slightly) more grown-up look, courtesy of the Italian fashion designer Roberto Cavalli. In creating the costumes for the comeback tour, Mr. Cavalli opted for color-coordinated looks made of metallic and jewel-tone fabrics.

The designer said he was mindful of the group’s longtime motto: Girl Power. But while the outfits are derivative of the look each Spice Girl sported a decade ago, they also reflect that the band members are no longer girls; they’re 30-somethings — with six children among them. “They wanted to remain true to their original characters and personalities,” Mr. Cavalli wrote in an e-mail to The New York Sun. “We worked with all of the images of what they wore in the past years and then reinvented their signature looks in a modern and more mature way.” For Ms. Beckham, Mr. Cavalli designed several costumes of bustier tops and matching leggings so tight they appear to be spray painted on. The most eye-catching among the ensembles, cut from a gold foil-like material, recalls C-3PO from “Star Wars” — and looks as constricting as body armor. It’s a wonder Ms. Beckham manages to breathe in it, let alone sing and dance in front of thousands of fans.

In the 1990s, Geri Halliwell (“Ginger Spice”) was, perhaps, the most outrageous dresser of the crew. She famously showed up for the 1997 MTV Video Music Awards in a leotard bearing the American flag’s stars and stripes and matching high-heeled sneakers. Her outfits, while still sexy, have been toned down considerably. On this tour, she wears a draped, silver blouse with an asymmetrical neckline, paired with white shorts. Another look is a beaded gold minidress that resembles a figure-skating costume. Meanwhile, Melanie Brown (“Scary Spice”) has ditched the midriff-baring outfits and thigh-high, platform boots in favor of superhero-like shiny unitards — in squeaky silver, as well as a giraffe print — and high-heel boots that only go to the knee. And although Ms. Bunton’s costumes stay true to her sweet “Baby Spice” persona, they are noticeably longer and roomier to accommodate the new mother’s figure.

Mr. Cavalli also infused some glamour into the costuming of Melanie Chisholm (“Sporty Spice”). While, in the past, her outfits have looked like little more than glorified workout gear, her new pantsuit ensembles are bedazzled with feathers, sequins, and more.

After the Spice Girls announced their reunion last summer, Ms. Beckham, who attends fashion shows the world over, approached Mr. Cavalli about designing the onstage outfits. “Everything came together very fast soon after that, and the costumes were completed in only three months,” he said.

Mr. Cavalli said he hopes the costumes get across the message “that each and every woman has a unique personality, and you can be glam, sport, posh, etc. all at once.”

During a concert last week at Nassau Coliseum on Long Island, each Spice Girl was allotted solo stage time. Ms. Beckham used hers not to sing, but to strut across the stage, as if it were a runway — with Madonna’s “Like a Virgin” playing in the background.