Olivia Newton-John's film career was brief but immortal

Going entirely off the numbers — record sales, Grammy awards, cumulative years spent working in a chosen medium — the late Olivia Newton-John was an extremely successful singer with a brief acting career. In the span of a couple years, she starred in 1978's Grease, which made a lot of money, and then in 1980's Xanadu, which did not. Her music career skyrocketed in 1981 with "Physical." After the mid-'80s, Olivia Newton-John, the actress, was mostly Olivia Newton-John, the cameo, playing herself here and there on sitcoms and Glee.

Grease's success was bigger than money, though. The Broadway adaptation was a megahit out the gate — a beneficiary, no doubt, of the nostalgia that also sent Watergate-exhausted citizens to American Graffiti and Happy Days. At the time, Newton-John was a 30-year-old with a decent international music career. Grease made her an icon of teenaged yesteryear. She's a specific American vision, even if the movie made Sandy Australian, and it should be the thankless role. Sandy wears frilly neck-to-toe pajamas at a boozy slumber party, and vomits after one sip of dessert wine and one drop of pierced-ear blood. (She also has to share the screen with Stockard Channing's Rizzo, a cynical hedonist who would rock on Euphoria.)

Paramount/Rso/Kobal/Shutterstock Olivia Newton-John in 'Grease'

But Grease is always weirder than it has to be, and Newton-John's performance sums up the uniquely appealing blend of retro sweetness and sardonic camp. In theory, Sandy's arc trends from virginal wet blanket-ing to va-va-voom leather sensuality — or, put another way, from "We made our true love vow" to "I need a man who can keep me satisfied." The early scenes certainly depend on Newton-John's wide-eyed innocence versus the "rough" world of Greasers and Pink Ladies and cigarettes. Her Sandra Dee persona gets defined in "Summer Nights," the he-said-she-said duet that has impressively circled the cultural barometer from dorky-romantic-cheesy to problematic-erotic-offensive. It gets a bad rap for jerky maleness plus some seemingly rigid gender norms, with good-girl Sandy apparently singing about love while hotheaded Danny Zuko (John Travolta) sings about lust.

I guess this is where I admit that I've loved Grease forever, that I think "Summer Nights" rocks, and that I fully believe the song works because Newton-John carries a light self-awareness, plus there's the considerable artillery of her singing voice. Sandy's no dope. Danny might get all the horny gyrations, but you can tell she's singing about something intense around the chaste margins: getting physical, bodies talking. This is one reason why Grease is a perfect family movie designed to blow kids' minds years later, when they suddenly realize there's a broken condom subplot. Newton-John's shimmering sweetness is key to that stealth-missile charm. Surely nothing too nasty can be going on here. After all, Sandy is in this movie!

Newton-John was already a successful musical act, country by way of Australia and the United Kingdom. Grease pretty much stops to film her all alone for "Hopelessly Devoted to You," a torch song much wearier than whatever version of youth Sandy is supposed to represent. And then the ending features her transformation, with big hair and skintight black clothes. If this were Reefer Madness, she'd be a fallen woman. If it were Taxi Driver, she'd be leaving the squares behind for life in the Big Bad City. Instead, Newton-John and Travolta dance through a carnival and fly off in a convertible, looking just married on their way to heaven.

So the movie is a journey from sweet monogamy to sexy monogamy. Travolta and Newton-John had chemistry, and looked great dancing together. Given the Grease phenomenon, it's possible she could've had a serious film career in a reality where musicals were being made. She was more singer than actor, but an earlier showbiz ecosystem knew how to play talents off each other: Match an ace dancer with a comedy guy, or pit a real singer against a tone-deaf looker. Instead, Newton-John got Xanadu, which begins when demi-goddesses come to life off a mural and explode into Santa Monica rays of skating light. She's Kira, a muse who inspired people like Beethoven, though it's unclear if she also inspired Beethoven to open a dance-off roller disco.

Everett Collection Olivia Newton-John, Gene Kelly, and Michael Beck in 'Xanadu'

The moment was not kind to Xanadu, which seemed to be bungling a whole Old Hollywood thing (Gene Kelly!) and a whole trendy thing (skate dancing!). It seemed to mainly exist as the springboard for "Magic," a number-one hit for Newton-John. That song's success paradoxically shined a harsher light on the film's own limp box office and flatlining reviews.

But by the time I watched Xanadu a generation later, you could bask in it with zero irony. If Grease was a perfect '70s dream of the '50s, Xanadu anticipates what all the retro-'80s entertainments would try to be in the 21st century: beach-y, dance-y, montage-y, excessive above all. (The decade in seven words from the title track: "Your neon lights will shine for you.") Newton-John pops up as a wartime ballroom dancer and a film noir femme fatale, and then the climax dresses her as a honky-tonk sheriff, a tiger-striped pop star, and some kind of alien empress. One light joke is that Newton-John is only ever Newton-John: adorable when she's vampy, cheeky when she's ethereal. I think Kira is supposed to be a mystery, but Newton-John looks (to the film's cheerful credit) just happy to be here.

Then there's the torch song, "Suspended in Time," the performance that you simply have to watch today if you're looking for a good cry. By this point in Xanadu, Kira is back in the glowing tronscape beyond space and time where the muses must live forever alone, and she's begging unseen gods to free her for a night of roller-romance with the reckless album-cover artist she loves. The sequence is unadorned in a way that could seem lazy: just one long approaching shot on Newton-John, who's encased in a pre-digital heavenly light that reads today as a Tim and Eric special effect. It's all amazing, and so is she. For all the excess swirling through Grease and Xanadu, and all the wind machines tickling her hair during the solos, there was always something unadorned about Newton-John on screen. A voice like that you don't need to fake — or it could be that movies were always a bit of a lark for her.

Just one year later, in the music video for "Physical," Newton-John was transformed again. Short hair, aerobic chic: It was the look. The video's another stealth missile, shrouding lyrics that are entirely about screwing in visuals about, like, the gym. Of course, all the glistening male hot bodies invite the female gaze, not to mention a loyal gay fanbase. There's the suggestion that all the attractive dudes are overweight normals dreaming of the men they want to be.

Is Newton-John playing muse again, making their macho-man dreams come true? Is she on the hunt herself? And if so, is the gag that she's getting cluelessly ditched, overlooked by a bunch of sweaty muscle guys who are actually just really into each other? Romance was always kind of a joke for her on screen — until she started singing about another kind of yearning, something almost spiritual. Hopeless devotion suspended in time: That's the way it should be.

Related content:

• Olivia Newton-John, Grease star and Grammy-winning singer, dies at 73

• John Travolta posts tribute to late Grease costar Olivia Newton-John: 'Your Danny'

• What made Olivia Newton-John 'horrified' about 'Physical'

• Olivia Newton-John and John Travolta reprise their Grease characters for the first time ever