By today's standards, some of the depictions of teenage life seen in Grease do not sit right with a modern audience.
But Olivia Newton-John, who played the lead role of Sandy in 1971 musical, has said that it's not right to judge the film by today's standards.
When the movie was replayed on TV over Christmas, many took to social media to pick up on misogyny, homophobia and racism.
Now, speaking on the A Life of Greatness podcast, she said: “I think it's kind of silly. I mean, this movie was made in the 1970s about the 1950s.
“It was a stage play, it's a musical, it's fun. It's a fun movie musical not to be taken so seriously.
“We need to relax a little bit and just enjoy things for what they are. I didn't see it like that at all, I think it's a fun movie that entertains people.”
The versions of the movie are often edited for broadcast, notably the song Greased Lightenin', which features numerous expletives and sexual references.
Watch: Olivia Newton-John defends 'Grease' against sexism claims
In the movie, John Travolta's character Danny, having met Newton-John's character Sandy over the summer, returns to school to rejoin his leather-clad gang of drop-outs.
But when Sandy arrives at Rydell High, she finds a very different young man, and rather than stick to her prim ways, transforms herself in order to snare him, wearing skin-tight trousers and smoking cigarettes by the film's climax.
One viewer called the film, as it aired on Boxing Day at 5pm on BBC1, a 'sexist piece of s**t'.
Many others weighed in on Twitter.
Ahhh man. Just watching #Grease one of my favourite films and it’s so of its time. Misogynistic, sexist and a bit rapey.
— Dr Kelly 🔶 💙 (@KellyQuilt) December 26, 2020
Grease really has a whole song where Danny is sad that Sandy is mad at him trying to rape her ????
— director saz (@sarahlostctrl) December 26, 2020
Crazy watching Grease as an adult and realising a song as seemingly innocent as “Sandy” is just Zucco moaning cos he can’t rape his gf in a car park
— Will Truefitt (@will_truefitt) December 26, 2020
I wish I could watch grease without getting angry at how sexist it is x x x
— nnnneeeauhhh (@niajade_) December 26, 2020
Grease was my favourite musical growing up. Still good but now I know how good it would’ve been if you know: not for racism
— V🌍 (@sincerelyVJB) December 26, 2020
Newton-John has retreated from acting, since her most recent diagnosis of breast cancer in 2017.
She has since become an advocate for the use of cannabis for treatment of cancer and other illnesses.
Watch: Olivia Newton-John won’t take the coronavirus vaccine