The Australia Day debate opened to an international audience on Wednesday when Hollywood superstar Chris Hemsworth shared his reasons for not celebrating his country’s national holiday.

The 38-year-old actor, best known for playing Thor in the Marvel Cinematic Universe, shared a series of posts on Instagram explaining the history of the Australia Day controversy and why the date is offensive to Aboriginal people.

January 26, which marks the raising of the British flag on Australian soil in 1788 after the First Fleet arrived in Sydney Harbour, is considered a day of mourning for many First Nations people, who instead prefer to call it Invasion Day or Survival Day.

Speaking out: The Australia Day debate opened to an international audience on Wednesday when Hollywood superstar Chris Hemsworth (pictured) shared his reasons for not celebrating his country's national holiday

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Speaking out: The Australia Day debate opened to an international audience on Wednesday when Hollywood superstar Chris Hemsworth (pictured) shared his reasons for not celebrating his country’s national holiday

Many of Hemsworth’s fans from overseas were surprised to learn Australia’s national day is so closely tied to its colonial history.

‘I had no idea about this. Thank you for sharing,’ one person commented, while another added: ‘We have learnt something new, thank you.’

A third wrote: ‘They should be teaching this in primary school but they don’t because kids aren’t allowed to know bad things have happened.’

'Trauma': The 38-year-old actor shared a series of posts on Instagram explaining the history of the Australia Day controversy and why the date is offensive to Aboriginal people

Flag: He also shared this photo of the Aboriginal flag made up of black, yellow and red hearts

‘Not many people know the dark history of Australia,’ another agreed.

One fan commented: ‘I understand more and more why the date needs to be changed. We cannot invalidate the struggle of First Nations people.’

Hemsworth, who lives in Byron Bay, NSW, has previously called for the date to be changed out of respect for Indigenous Australians.

He isn’t the only Aussie speaking out against Australia Day.

'I had no idea about this!' Many of Hemsworth's fans from overseas were surprised to learn Australia's national day is so closely tied to its colonial history

Thousands of people joined Invasion Day protests in cities across Australia on Wednesday.

A long-running campaign to abolish Australia Day or change the date has a growing number of Aussies feeling uneasy about the national day of celebration.

Indigenous activists, and many other Australians, now regard the day British settlers who first landed in Port Jackson on the First Fleet in 1788 as an event to be mourned, not celebrated.

Change the date: Hemsworth, who lives in Byron Bay, NSW, has previously called for the date to be changed out of respect for Indigenous Australians. (Pictured with his wife Elsa Pataky)