Brad Pitt has admitted to decades of heavy drinking and marijuana use in his first extensive interview since splitting with Angelina Jolie last year.

The 53-year-old actor told GQ Style in the interview published Thursday morning (AEST) he and Jolie were now committed to resolving matters amicably and privately after watching his family be “ripped apart”.

Jolie’s sudden announcement in September 2016 that she was filing for divorce sent shockwaves through the celebrity world.

The couple known as ‘Brangelina’, who married in 2014 and have six children, were initially embroiled in a bitter child custody dispute, with Pitt investigated for possible child abuse after losing his temper in front of some of the children.

The Oceans 11 star was cleared of the allegations, and in January he and Jolie agreed to use a private judge in their divorce case

The actor says he has since quit drinking and was undergoing therapy after turning to alcohol in the past year to cope with his issues.

“I was boozing too much,” Pitt said “It’s just become a problem. And I’m really happy it’s been half a year [sober] now, which is bittersweet, but I’ve got my feelings in my fingertips again.”

Brad Pitt covers @GQStyle's Summer 2017 issue, photographed by Ryan McGinley https://t.co/kd0qjlEj76 pic.twitter.com/45JZvC1cn3

— GQ Magazine (@GQMagazine) May 3, 2017

Pitt said the split with Jolie, 41, had been a “huge generator for change”.

“I can’t remember a day since I got out of college when I wasn’t boozing or had a spliff, or something.

“I’m really, really happy to be done with all of that. I mean I stopped everything except boozing when I started my family. But even this last year, you know – things I wasn’t dealing with. I was boozing too much,” he said.

Pitt said he loved wine, adding “truthfully I could drink a Russian under the table with his own vodka. I was a professional. I was good”.

Regarding the divorce, Pitt said he and Jolie had decided to abandon the path of “vitriolic hatred” and work together to sort out their issues.

He will not allow his children – 15-year-old Maddox, 13-year-old Pax, 12-year-old Zahara, 10-year-old Shiloh and 8-year-old twins Vivienne and Knox – to be dragged through an ugly court dispute over custody.

“I just refuse,” Pitt said. “And fortunately my partner in this agrees. It’s just very, very jarring for the kids, to suddenly have their family ripped apart.”

Pitt and Jolie released a joint statement in January saying they would be sealing all legal documents pertaining to their divorce in a bid to protect their children.