For the Grease generation, Olivia Newton-John's illness is hard to accept

I know it so well. Every frame of it. Even now, if I chance upon a screening of it on TV, or call up key moments on YouTube, the magic still remains.

A film critic once called Grease “an ode to young love that never gets old,” which is a pretty fair description. There is Olivia Newton-John playing a teenager (she was actually 29 at the time of filming) skipping across the school yard in that yellow cardigan, her knowing refrain (“He showed off, splashing around”) a hilarious counterpart to John Travolta’s braggadocio (“I saved her life, she nearly drowned”).

Or the moment when she is teased at the “Sandra Dee” sleepover. And of course the classic: walking down the wooden staircase in a virginal nightie accessorised with an Alice band, explaining how she was “Hopelessly Devoted”.

We all were. We were all hopelessly devoted to Newton-John – or as the Radio 1 wags had it back in those more innocent times, Olivia Neutron-Bomb.

We loved her. We loved the way her perfect soprano was capable of mixing pain and pleasure in the same lyric. We hated it when she was teased by Rizzo (whom we also loved, of course, but in a different way). But most of all, we loved her when she appeared at the fairground in the spray-on black trousers, smoking (smoking!) and expertly dancing through the Cakewalk ride, and kicking Travolta over in her red mules and a bubble curl. “Feel your way!”

The poster of that moment, featuring Newton-John in her strapless black top, snuggling up to Travolta in his black T-shirt was on thousands, probably millions, of teenage bedroom walls in 1978. “You’re The One That I Want” was at number one for nine weeks that summer. We performed “Summer Loving” on the desks every lunch hour at school. We all knew the film backwards, because we had all seen it five, six, even 10 times.

This was in the era before instant availability online, before even video had arrived on the mass market. That meant you could only see it once a week, but never mind; we all queued up at the ABC cinema and watched it play out every Sunday for eight weeks.

Nowadays, blockbusters only screen nationally for a matter of days. Grease, which cost $6m to make, and has since grossed nearly $400m, gripped the nation for months. I remember my mother having a serious debate with a neighbour about whether it was suitable viewing for my little sister, then aged eight (the consensus, mercifully, was yes).

Forget Jaws, even Star Wars. Those era-defining films were epic, certainly. But were they lovable? La-La Land, its cynical modern counterpart, simply cannot hold a candle to the optimism, romance and joy of Grease. Even a cursory glance at “We Go Together”, the ecstatic closing sequence in the fairground, will attest.

So the news that Newton-John is grievously ill grips at a certain generation who grew up looking to her as something of a lodestar of our own happiness and maturation. We laughed at her innocence in Grease, but cheered her on when she was transformed into a badass.

We didn’t really take her seriously when she wanted to get “Physical”, on the eponymous single. She wasn’t Donna Summer, she was like a big sister, but we warmed to her attempt to be sexy. We loved her when she went full disco with “Xanadu”, that effortlessly sunny voice reaching madly high notes with a super-electronic backing courtesy of ELO.

Totally middle of the road, but totally lovable. She always sounded like she was smiling when she was singing.

Even when you heard her voice coming out of the radio, and couldn’t see her face, you knew Newton-John was happy.

To millions of middle aged women like me, the sad news of her returning illness will be hard to compute. To us, she is still Sandy, the girl who got the boy, smiling back at us out of the red Greased Lightning convertible as the couple drive off into the clouds.