Rob Kardashians' famous family urged him to take down his insulting online post aimed at his sister Kim Kardashian West.

Rob Kardashian

Rob Kardashian

The 28-year-old designer's relatives - including sisters Khloe and Kourtney Kardashian and mother Kris Jenner - were reportedly stunned by his behaviour on Instagram over the weekend and advised him to take down the disturbing post aimed at his sibling.

A source told RadarOnline.com: "The Kardashian family urged Rob to take down the post, but he refuses to do so. At this point, it is too late anyways.

"No one can believe that Rob would do such a thing as he did this weekend. It is one thing to talk to the family about how he feels about Kim, but it is a completely different story to put her on blast like he did. Kim would never do such a thing to Rob, or to any of her other siblings for that matter."

However, it is believed Rob, who once claimed he was a father on Twitter before deleting it hours later, is suffering from "depression" and his behaviour isn't out of character.

A source added to People: "He has a funny sense of humour and posts weird things and then deletes them. It's just him."

The former reality TV star hit the headlines on Sunday evening (22.03.15) when he uploaded a photograph of psychotic murderer Amy Elliott-Dunne, played by Rosamund Pike, covered head-to-toe in blood from a gruesome scene in the movie 'Gone Girl.'

He captioned the spooky image: "This is my sister kim , the b**ch from Gone Girl,,, (sic)."