Grease's impact continues to electrify 45 years after it premiered.

There's no denying the beloved 1978 musical has transcended cinema, leaving behind an indelible fashion and beauty legacy. With a kaleidoscope of colorful outfits, bold makeup looks and hair teased to the high heavens, Grease's style moments are embedded in pop culture.

For one, the film is set in 1958, a time period that easily lends itself to glamorous looks. Plus, it follows the love story of high schoolers Danny Zuko (John Travolta)—the original f--k boi and leader of the T-Birds, whose signature style is a mix between James Dean and Elvis Presley—and goody-two-shoes Sandy Olsson (Olivia Newton-John), who later transforms into a bad girl with her iconic black skintight pants, matching off-the-shoulder top and striking red lip.

"When I walked out onto the set in them for the first time, I got quite the reaction—everyone stopped," Olivia told InStyle in May 2018 of her famous femme fatale look. "It was unlike anything I'd worn before. After we wrapped the film, I was lucky enough to get to keep the costume."

The late actress, who died in August 2022, recalled the perfect fit of the black, red-lined leather jacket she wore in the carnival scene. However, the pants—which went on to inspire American Apparel's best-selling Disco Pants and Kim Kardashian's SKIMS Disco Pant line—were an entirely different story.

"I remember going into the wardrobe trailer with our costume designer, Albert Wolsky, and trying on the outfit for the first time," Olivia remembered. "The pants were fantastic too, but because they were actually from the '50s, the zipper was broken, so I had to be stitched into them."

Despite literally being sewn into the tight-fitting bottoms, Olivia didn't let it restrict her memorable performance of "You're the One That I Want."

After all, the all-black vixen look—which mirrors the T-Birds' uniform—marks a pivotal moment in the film and encapsulates the emancipation of her character. From the hot number to the teased-out curls and look-at-me-makeup, this showcases Sandy's metamorphosis into a good girl gone bad.

"Olivia Newton-John couldn't wait to get into the sexy spandex," the costume designer revealed to Stylist U.K. in 2012. "She hated the goody-goody look Sandy has to wear. When she came out in those tight black spandex pants, the way she walked, the way she behaved—it completely changed."

Olivia echoed similar sentiments in her 2018 autobiography, Don't Stop Believin', while discussing the dichotomy of playing two Sandys.

"Sandy #2 was deliciously wild," she wrote, "and there was a great buildup of excitement inside me to finally bring her to life."

While the risqué look proves Sandy's willingness to change, there's also an underlying message that the times are evolving.

The daring design represents the start of a new fashion era, as the rigid style of the 1950s slowly begins to fade. Additionally, that same idea was happening IRL when the film premiered in 1978, with the bohemian trend of the '70s going out of style and the 1980s ushering in a new wave of strong makeup, perm hairstyles and body-hugging fashion. Think: Olivia's 1981 hit song "Physical" and the skintight music video looks.

Of course, Sandy wasn't the only one to switch up her signature style in the film. 

Danny also undergoes a transformation at the end of the musical by swapping out his cool leather jacket for a crisp white letterman. And as minor as this change is, it's noticeable enough to his T-Birds crew.

"I can't believe it. Danny Zuko turned jock," Doody (Barry Pearl) says to the ringleader, as Sonny (Michael Tucci) interjects, "What are you doing, deserting us?"

Danny replies, "You guys can't follow a leader all your lives. Come on, guys. You know you mean a lot to me, it's just that Sandy does, too, and I'm going to do anything I can to get her."

The rest, as they say, has become history.

Four decades later, you're still likely to spot a couple dressed as Sandy and Danny for Halloween. It's also been a source of inspiration for countless runway collections, including Moschino, Jean Paul Gaultier, Mugler, Saint Laurent and many others.

But we'd be a fake and a phony if we didn't tell you more, tell you more about the importance of the musical's other memorable fashion moments and the concept behind them.

When piecing together the looks for the cast, Albert pulled references from the 1950s greaser subculture that the T-Birds and their girl gang The Pink Ladies are part of. But he also left room for interpretation and imagination.

"I started out trying to be realistic," Albert previously told Stylist U.K. "But the director wanted more color. I ended up thinking, 'These people are all meant to be in high school and, yet, they are coloring the grey streaks in their hair. Why the hell am I trying to be realistic? It's ridiculous!' So we just went mad with it."

Sandy's wardrobe alone features a rainbow of pastels. For her first day of school at Rydell High, Sandy armors herself with a bright yellow poodle skirt, matching cardigan and white button down. The added detail of her floral hair accessories is a subtle reminder of her innocence and girliness.

It's a stark contrast to Pink Ladies leader Rizzo (Stockard Channing), who rules the first day of school in a black body-hugging dress with popped collars. And it's only when Rizzo believes she's pregnant that her wardrobe changes from sexy to sweet, as she wears a soft cashmere sweater in pastel purple during her number "There Are Worse Things I Could Do."

And when it came time for prom night, the costumes and the characters went together like rama lama lama ka dinga da dinga dong.

Sandy dons a white frilly dress for prom, a wholesome, pure choice compared to Rizzo's plunging red polka dot look and the low-cut strapless gown Marty (Dinah Manoff) wore to catch the eye of hot shot radio announcer Vince Fontaine (Edd Byrnes).

And then there's Frenchy (Didi Conn), who looks like a beautiful blonde pineapple with her bleached hair and matching getup. Throughout the film, we see that Frenchy isn't afraid to experiment with her style but still sticks to what's trendy in 1958.

Overall, the style in Grease has stood the test of time and we saw it surge in popularity once more after the prequel series Grease: Rise of the Pink Ladies premiered in April on Paramount+. The show explored the origin story of the girl clique, while also sparking a new wave of vintage glam. 

It turns out Grease is still the word.

(This article was originally published on April 7, 2023 at 3:00 a.m. PT.)