Brad Pitt's son reportedly branded him a "world-class a**hole" and an "awful human being" in a withering post on Instagram.
Pax Thien Jolie-Pitt, 19, allegedly published the rant against his adoptive father in a post on his private Instagram story on Father's Day 2020, when he was 16.
The teenager allegedly claimed the Hollywood star made his four youngest children "tremble in fear", and "made the lives of those closest to [Pax] a constant hell".
Pax was adopted by Pitt's ex-wife actress Angelina Jolie from a Vietnamese orphanage near Ho Chi Minh City in 2012, and was later formally adopted by Pitt. The couple, who have six children together, separated in 2016.
The Instagram post from 2020, reportedly written by Pax, says: "Happy Father's Day to this world-class a***hole"!
"You time and time and again prove yourself to be a terrible and despicable person.
"You have no consideration or empathy toward your 4 youngest children who tremble in fear when in your presence. You will never understand the damage you have done to my family because you are incapable of doing so.
"You have made the lives of those closest to me a constant hell. You may tell yourself and the world whatever you want, but the truth will come to light someday.
"So, Happy Father's Day, you f***ing awful human being!"
The rant was posted along with a photo of Pitt wearing black tie, while accepting an Academy Award for best supporting actor, for his role in Once Upon a Time...in Hollywood, which he won in 2020.
Posts made on Instagram stories are automatically deleted after 24 hours, but a screenshot of Pax's alleged post from three years ago has gone viral this week.
MailOnline claims a source has confirmed the private Instagram account from which the post was made belongs to Pax.
"It's the account he uses for friends – friends from school mostly," the source reportedly said.
Pitt and Jolie have five other children: Maddox, Zahara, Shiloh, Vivienne and Knox.
The couple married in 2014, but split two years later, ending their 12-year relationship. Following a lengthy custody battle, Jolie won custody of their five youngest children, who were minors at the time.
Filing for divorce in September 2016, Jolie cited "irreconcilable differences" between her and Pitt.
The FBI and the Los Angeles Department of Children and Family Services then confirmed they were investigating Pitt for alleged child abuse, following an incident on the family’s private jet.
The actor was accused by an anonymous person of getting physical with the couple's eldest child, Maddox.
According to TMZ at the time, “the details of precisely what happened” were “murky.” But it was reported that Maddox had stepped in to verbally stand up for his mother during a fight with Pitt - who then lost his temper.
A source close to Pitt told People he was “was drunk, and there was an argument between him and Angelina!".
“There was a parent-child argument which was not handled in the right way and escalated more than it should have.”
Pitt has since been cleared of all allegations.
The actor hasn’t made any comment about the allegations but has been open about his drinking and drug use.
In a May 2017 GQ interview, Pitt revealed he had quit drinking and smoking cannabis. “I can't remember a day since I got out of college when I wasn't boozing or had a spliff, or something," he said.
"And I'm running from feelings. I stopped everything except boozing when I started my family. But even this last year...I was boozing too much," he told the magazine.
"It's just become a problem. You either deny them all of your life or you answer them and evolve."