There's allegedly a brewing feud that looms between Selena Gomez and Kourtney Kardashian as the "KUWTK" star is reportedly hooking up with Justin Bieber.

According to Hollywood Life, the looming feud exploded into an all-out confrontation as Selena Gomez reportedly asked Justin Bieber directly if he's hooking up with the much older Kourtney Kardashian.

"Justin and Selena have spoken since the news broke that he's been hooking up with Kourtney," the website said. "Selena asked him point blank if it was true and Justin didn't deny it. He was kind of flattered that she asked because in his mind that means Selena still cares. But Selena doesn't see it that way at all. She's 100% into Niall [Horan]."

An article from Us Weekly claimed that Justin Bieber and Kourtney Kardashian only started hanging out when the "KWUTK" star decided to explore the world more following the split from Scott Disick.

"Justin started hanging out with Kourtney alone because she started going out more," the insider claimed. "Remember, she never really went out before, so he's been showing her a good time."

"He actually goes over a lot to see her kids, and they love him," the source added of Justin Bieber's relationship with Kourtney Kardashian's three kids with Scott Disick.

While Kourtney Kardashian was rumored to be hooking up with Justin Bieber, Selena Gomez is said to be dating One Direction member Niall Horan.

But the "Come & Get It" singer shut down the dating rumors.

Talking to Entertainment Tonight, Justin Beiber's ex appeared to be mortified when asked if the rumors are true.

Oh my god! No," she said, before adding of Niall Horan, "I love him, I always have. He's amazing."

"I just felt like for me, I am in a place where it is my right to say something and defend myself, because I'm always kind, I'm always nice," Selena Gomez added. "Every now and then I deserve to say what I feel."

To date, Selena Gomez and Kourtney Kardashian have yet to respond to the alleged feud over Justin Bieber.