Blac Chyna and Rob Kardashian
Blac Chyna and Rob Kardashian are rumoured to be dating Frederick M Brown/Ethan Miller/Getty Images for BET

Kylie Jenner is unhappy over reports that Rob Kardashian is dating Blac Chyna. The 27-year-old model posted a picture of herself apparently cuddling up to the E! reality TV star on Instagram sparking dating rumours.

In the image, Tyga's former fiancée is seen cosying up with Kim Kardashian's brother's tattooed arm. She captioned the image: "The beginning ☘"

"Kylie is livid," a source told People. "She feels super betrayed and can't understand why someone in her own family would stab her in the back like that."

The 18-year-old TV star and Chyna have not been on good terms ever since Jenner started dating the Rack City rapper back in late 2014. Tyga and Chyna have a son together named King Cairo.

Meanwhile, the 28-year-old sock designer has remained out of the spotlight since gaining weight. Rob did not attend Kim and Kanye West's wedding in Florence, Italy, on 24 May 2014, after she reportedly commented about his weight gain.

In a Rolling Stone interview, Kim had spoken of her brother. "It's not that mysterious, what's happening with Rob. He has gained weight. He feels uncomfortable being on the show, and that's OK. Do I think he smokes weed, drinks beer, hangs out and plays video games with his friends all day long? Yes," Kim told the publication.

Meanwhile, Kris Jenner had revealed that Rob is getting back on track with exercise and healthy eating habits. "He's doing terrific. Robert's good. He's working out and eating [well], so he's on a good path right now," she told Entertainment Tonight, according to The Mirror.