Eternals was never intended for release while the COP26 climate summit was taking place, but the timing does seem strangely appropriate.

Pushed back from hitting cinemas in 2020 due to the pandemic, the latest big-budget film in the Marvel Cinematic Universe tells the story of a disparate group of superheroes who find that, with the destruction of Earth at stake, they are more powerful when they work together.

This storyline, coupled with beautiful cinematography showing our planet at its best – thanks to filming taking place in real locations rather than closed-off sets – means it’s hard not to draw comparisons between the messaging in the film and those coming out of the environmental conference in Glasgow.

With an all-star cast featuring Angelina Jolie, Salma Hayek, Gemma Chan, Kit Harington, Kumail Nanjiani and Richard Madden, it’s a high-profile way of spreading the message about saving the planet.

Harington, who plays human Dane Whitman in the movie, told Sky News he thinks Hollywood has its own part to play in helping push the green agenda.

“It’s important that the industry I’m in, the entertainment industry, not only speaks about that, but also acts on it as well – that the sets we’re on are sustainable, that we reduce our flight numbers where we can,” he said.

“As far as this movie goes, it is talking about a group of eternal beings who’ve seen us as humanity go from 7,000 years ago… and has seen us destroy each other, kill each other, but also show love to each other and come through things.

“I think it’s a bit of a love letter to the world and it’s a love letter to humanity, and it’s full of hope as well as warnings – and I think it’s a really important movie for our time for that reason.”

Chan, who plays superhero Sersi, said she thinks themes of environmentalism are being reflected in the art that is being produced at the moment.

“Hopefully it will come through in the storytelling that we see. I’m doing a project next called Extrapolations [where] climate change is the backdrop to the setting of the show, so I think we’re probably going to see that more and more; it’s the reality that we’re all living in, that we all have to deal with.

“I think with this film as well, the message for me is that we can’t achieve anything by ourselves. We have to work together, we have to try and solve these problems together.”

For Nanjiani, who plays the superhero Kingo, the conversation around climate change needs to change.

“I think it’s so absolutely unbelievable that environmentalism has become politicised,” he said. “If anything has shown us this last year and a half, we’re all on the same rock and if something happens here it’s all our problem – doesn’t matter what you look like, where you live, what the borders that we’ve drawn are, it affects us all.

“Environmentalism obviously is something that affects every single one of us, so it’s pretty frustrating that it’s become a polarised topic.”

Salma Hayek, who plays Eternals leader Ajak, agreed the pandemic has highlighted the need for people to work together.

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“I think that COVID gives us a taste of it, how we’re in it together and we all have to do something. It’s not like you can wait for the governments to fix it.”

Eternals has a very different feel to the Marvel movies that have come before, perhaps because it was directed by Oscar-winner Chloe Zhao.

Hayek said Zhao is one of the reasons she wanted to be involved in the film.

“I’m so proud of them for choosing this amazing woman, Chloe, who has the capability to do very huge scope and intimacy at the same time, and beauty and imagination, creativity,” she said.

The Eternals cast also includes a deaf superhero, played by Lauren Ridloff, and some of the dialogue is in ASL (American sign language).

Harington said the addition of the character sets this apart from previous Marvel films.

“The fact we’ve got a deaf superhero talking to deaf kids all over the world in a language they understand, dressed in a superheroes outfit – that’s fantastic,” he said. “That’s what’s special about this movie.”

Chan, who starred in Crazy Rich Asians – which featured a majority cast from Chinese descent – said it’s time for diversity on screen to become the norm.

“[Eternals] felt like a kind of natural evolution. I think it’s a great thing that there may be many young girls and boys who might see themselves represented in a film like this, maybe for the first time.

“But I also hope we’re moving towards a point where it’s just normalised, and it’s not a big deal to have a cast like this.”

Eternals is out in cinemas on 5 November