Kim Kardashian's half-sister posted a short clip on social networking app Snapchat late on Wednesday (23Sep15), when she filmed Tyga while sitting with her legs wrapped around his waist.

Speaking into the camera, the hip-hop star said, "I don't f**k with nobody, I don't f**k with nobody. It's just me, my fiancee, this little dog I just got. I don't f**k with nobody."

The post sent fans into a frenzy, but it has since emerged Tyga, 25, appeared to be mocking an old interview with rapper Logic, which he had shared on Instagram earlier in the day.

It's not the first time Tyga and Jenner have sparked rumours of an engagement - the 18 year old had to dismiss marriage claims in July (15) after she was photographed wearing a diamond ring on her left ring finger.

Taking to Twitter, she wrote, "Not planning on getting married anytime soon".

The stars, who have been linked since last year (14), have been more open about their relationship in recent months. They made their red carpet debut together at the MTV Video Music Awards in Los Angeles last month (Aug15), while Tyga recently recruited Jenner to play his love interest in the steamy video for his track Stimulated, in which they openly kiss and cuddle.

The tune hit headlines over the summer (15) for its suggestive lyrics, in which Tyga seemingly raps about sex with the teenager.

He spits, "I'm stimulated/I'm at the bank, I'm penetratin'/I'm puttin' in, I'm penetratin'/I'm gettin' big, I'm stimulated... They say she young, I should've waited/She a big girl, dog, when she stimulated".