Things are getting nasty between Selena Gomez, 21, and Kylie Jenner, 16. After the public selfie posted by Justin Bieber on his Instagram featuring the youngest of the Kardashian brood, a close insider revealed to Hollywood Lifethat Selena Gomez thinks that Kylie is a "desperate," and "pathetic" "groupie".

The selfie posted publicly by Justin Bieber on his own personal Instagram account has racheted up the tension between his on-and-off girlfriend Selena Gomez. It can be remembered that the "Come & Get It" singer was pictured having fun with the Jenner sisters at Coachella before their sour and acrimonious falling out.

Justin Bieber allegedly took the 16-year old reality star as a date for Floyd Mayweather's fight in Las Vegas.

"Selena was not happy that Justin posted a selfie with Kylie. She thinks Kylie is desperate for attention and is a pathetic Justin Bieber groupie," revealed an insider to Hollywood Life.

When questioned about the friendship that blossomed during Coachella, the insider responded: "It was obvious at Coachella that Kylie had the biggest crush on Justin, she was flirting then and continues to flirt." The insider mentioned.

What does Selena Gomez think about the rumors that have been spreading about Justin Bieber dating Kylie Jenner?

"If Justin did in fact start dating Kylie, Selena would lose all respect for him. She thinks it would be so silly and childish," a close source reveals further to Hollywood Life.

This would probably the last time Selena Gomez would date Justin Bieber. The escalating tension between the crossed lovers has magnified to unprecedented levels after Selena Gomez unfollowed Justin Bieber and the Jenner sisters on Instagram. Moreover, the "Come & Get It" singer has been cleaning up her account-removing pictures of Justin Bieber and the Jenner sisters.

Could this really be the last time fans would be seeing "Jelena?"

Meanwhile, looking unaffected about the mounting Kylie-Bieber issue, Selena Gomez was pictured looking more beautiful than ever during the MET Gala. The singer donned a burgundy Diane Von Furstenberg gown. The former Disney actress graced the event alongside Jessica Alba and designer Diane Von Furstenberg.