By Staff Writer (media@latinospost.com) | First Posted: Apr 22, 2015 12:27 AM EDT

Selena Gomez used to sing Kendall Jenner "Happy Birthday" when the model turned 19 late last year. However, it appears that the two friends are now hitting a rough patch once more after the rumor mill churned out news that Kendall secretly got together with Sel's ex Justin Bieber.

"Selena's so furious after learning about the hook ups between the pair, that she's vowed to have nothing more to do with Kendall or any of the Kardashian/Jenners!" Hollywood Life said.

Looks like the singer is still far from being completely over her on-and-off boyfriend.

"Selena has heard that Kendall and Justin are hooking up and feels totally lied to, betrayed and stabbed in the back by Kendall," a source told the entertainment news site. "She doesn't know how long it's been going on, but she's convinced it's actually happening, and feels embarrassed and foolish. She doesn't even consider Kendall a friend anymore."

The frenemies were in a similar predicament last year, with the Biebs reportedly cosying up to Kendall at Coachella. However, the two patched up their friendship with the help of mutual friends late last year. It appears that the reconciliation didn't hold for long.

"Kendall and Hailey [Baldwin] started hanging out with Justin a lot, but Kendall kept insisting that they were just friends," the insider went on to reveal. "Selena even texted Kendall about it a little, so now she feels like Kendall just lied to her face."

"Those Instagram photos of Justin and Kendall at Coachella just confirm what Selena thought all along... That Justin was cheating on her with Kendall," another insider told Yahoo! Celebrity. "And it all started at last year's Coachella."

"It stings," the source added. "Seeing the recent pictures of Justin and Kendall together is like a stab in the back all over again. It's not that Selena wants to be back with Justin, it's more of a betrayal thing. She feels betrayed by Justin and Kendall."

It could be recalled that Justin and Kendall were recently photographed together by sought after photographer Mario Testino for a Vogue spread.

"The images show the good looking pair lounging on some sun beds, sipping drinks in the California sunshine," Express said about the photos. "Justin is topless, whilst a bikini-clad Kendall grins beside him."

Will Sel and Kendall manage to patch things up again after this episode? The 22-year-old had recently broken up with DJ Zedd, according to Hollywood Life, as it was reported that she still isn't really over Justin just yet.

"Zedd just felt like he would always be number two in Selena's life. He felt like he never really had her heart 100 percent. She would never admit that she's still in love with Justin, but that's how Zedd feels," a source told the site.

"Zedd adores Selena but can't figure out why she's still hooked on Justin. It's something he's given up trying to figure out," the source added.

Perhaps Zedd may find sympathy from Taylor Swift where Sel's obsession with Justin is concerned.

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