Rob Kardashian took a swipe at his sister Kim Kardashian West on his Instagram account on Sunday.

The 28-year-old star compared the 'Keeping Up With the Kardashians' beauty, 34, to the woman from "Gone Girl" - psychotic murderer Amy Elliott-Dunne played by Rosamund Pike - after deleting every other picture from his social networking account.

Alongside a photograph of Rosamund in character covered head-to-toe in blood from one of the gruesome scenes in the movie, Rob wrote: "This is my sister kim , the ***** from Gone Girl,,, (sic)."

The spooky post comes just days after Kim wished the sock designer a happy 28th birthday via a heartfelt message online.

She wrote last week alongside a throwback photo of them in Las Vegas:

"Happy Birthday to my one and only brother Robbie!!!! I love you so much and can't wait to share so many more memories with you! (sic)."

Kim and Rob reportedly fell out last year when he refused to attend her and husband Kanye West's wedding in Italy because he was reportedly so self-conscious about his expanding waistline.

Rob - who has battled with his weight over the past year - hasn't been seen in public for months and his sister Khloé Kardashian, 30, believes he's suffering with "social anxiety."

She said recently: "I just feel, especially over the last year, Rob has become very introverted and has a kind of social anxiety."