While Kylie and Kendall Jenner grew up together very close, tension might be brewing because Tyga's girlfriend is allegedly fed up of her older sister's success. At the age of 19, Kendall Jenner already managed to carve a reputation in the modeling industry.

"Kylie is always going to be playing second fiddle, and she absolutely hates it," said an insider to Radar Online. Kylie is just trying to do her own thing right now and develop a brand for herself that will outlast Kendall's minute of fame."

To allegedly prove her desire to be different from her sister, Kylie Jenner came up with her own hair extension line.

Previously, Kylie and Kendall Jenner collaborated for PacSun's summer collection. Apart from their apparel project, the two reality television stars also came up with their own novel, "Rebels: City of Indra."

Recently, the younger Jenner  shared a sexy photo on her Instagram account. Kylie Jenner was clad in a seemingly age inappropriate swin wear.

Recognizing the fact that she gained weight, Tyga's girlfriend captioned the photo:"behind the scenes. (yes I gained weight there I said it so u don't have too) :)."

Her penchant for sharing sexy photos made some fans speculate that the younger Jenner is trying to compete with her sister.

It isn't the first time that rivalry rumors between the two sisters surfaced. Last year, Heat World reported that the younger Jenner is willing to go under the knife to surpass her sister.

"Kylie's such a pretty girl, but she's found it difficult that her sister Kendall's modelling career has taken off so much more than hers. Kendall is a natural born model. Kylie says she's happy for her but, behind the scenes, all her friends know she's jealous," said the publication's insider.

Kylie Jenner, however, expressed that plastic surgery rumors about her are "insulting."