After a taking a lengthy hiatus from social media, Rob Kardashian took to Instagram on Sunday to slam his sister, Kim Kardashian.

Rob posted a still photo from the Oscar-nominated film, "Gone Girl," which details the life of psychotic fictional character, Amy Dunne, who attempts to fake her own death and frame her husband.

Alongside the photo of Rosamund Pike who plays Amy, Rob wrote, "This is my sister kim , the b*tch from Gone Girl."

 This is my sister kim , the bitch from Gone Girl,,,

A photo posted by ROBERT KARDASHIAN (@robkardashian) on Mar 22, 2015 at 10:38am PDT

Prior to posting the controversial photo, Rob deleted all of his Instagram photos. He also unfollowed and then re-followed his family members, TMZ reports. It is not clear whether Rob's photo is a sign of sibling rivalry or the result of his account being hacked. The Huffington Post suggests that Rob's diss to Kim comes as strange since a week prior, Kim posted a loving birthday message to Rob on her Instagram.

So far, no family members have responded publicly about the incident, but the Hollywood Life claims that Kardashian-Jenner matriarch, Kris Jenner, is allegedly furious with Rob's actions.

"Instead of seeing Rob's Instagram as a cry for help Kris is pissed that Rob is taking to social media to bash the family," says a Hollywood Life source. "She has told Rob to apologize to Kim but he has refused which is only getting Kris more heated."

Meanwhile, Rob's sister Khloe Kardashian recently revealed to WonderWall that he suffers from social anxiety and has been having a very difficult year.

"I just feel, especially over the last year, Rob has become very introverted and has a kind of social anxiety," Khloe revealed. "He's definitely not at his happiest place that he once was, and I know he can get to that happy place and he will."

Related