He's one of the biggest movie stars on the planet, and during an interview on The Project on Monday night, Brad Pitt proved nothing is off-limits.

The 55-year-old actor sat down opposite Carrie Bickmore to discuss his new movie, Ad Astra, when talk turned to his struggle with alcoholism.

When Carrie, 38, asked the star how important he felt it was to speak openly about his demons, he was happy to oblige.

Happy to talk: He's one of the biggest movie stars on the planet, and during an interview on The Project on Monday night, Brad Pitt, 55, proved nothing is off-limits

'I think it's important...' he began.

Brad then said that as human beings, we're essentially 'all the same', and everyone has their own struggles.

'Probably 97 per cent of us that makes us us is all the same, it's universal,' he continued.

Honest conversation: Brad sat down opposite Carrie Bickmore to discuss his new movie, Ad Astra (pictured), when talk turned to his struggle with alcoholism

'I think we all carry deep pains to different degrees and regrets, and we're very good, certainly in my culture, at burying those.'

He said it was important for him to speak out about what he has dealt with in order to move on and heal from it.

'It leads to a more well-rounded, certainly more comfortable existence within yourself, and greater peace of mind. And I find that you can enjoy the good stuff more,' he added.

Getting better: He said it was important for him to speak out about what he has dealt with in order to move on and heal from it. Pictured last week at the Tokyo premiere of Ad Astra

In an interview with The New York Times earlier this month, Brad opened up about his decision to get help, revealing he had spent 18 months in Alcoholics Anonymous following his September 2016 split with Angelina Jolie, 44.

'I had taken things as far as I could take it, so I removed my drinking privileges,' he told the publication.

Brad said his support group was composed almost entirely of other men, and he found their bravery encouraging.

Help: In an interview with The New York Times earlier this month, Brad revealed he had spent 18 months in Alcoholics Anonymous following his September 2016 split with Angelina Jolie. Pictured together at the Screen Actors Guild Awards in Los Angeles in January 2008

Amazingly, no one betrayed his trust by selling him out, with the star describing the experience as 'freeing'.

'You had all these men sitting around being open and honest in a way I have never heard,' he added.

'It was this safe space where there was little judgment, and therefore little judgment of yourself.'