It looks like there might be some pop star drama going on between Miley Cyrus, Demi Lovato, Selena Gomez and Taylor Swift after the Adore You singer allegedly hooked up with Gomez's ex Justin Bieber.

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On Wednesday, Life & Style reported that the four pop stars used to be close, but things changed when rumor got out that Cyrus had some sort of fling with the Boyfriend singer.

"Both Taylor and Demi know how heartbroken Selena's been, and they hate what Miley did to her," a source reportedly revealed.

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"All four girls used to be friendly, but when Selena heard Miley started making moves on Justin, it went downhill," they continued.

This drama could potentially lead to Swift talking smack on Cyrus.

"Taylor isn't shy about telling people she thinks Miley is a skank," another insider revealed.

According to the report, this issue could be the reason why the We Can't Stop singer didn't attend the Grammy Awards. Rumor has it that she would've had to sit near the other girls if she showed up.

"Just them RSVPing to an event is enough to keep Miley away," the source said.

Cyrus is currently on her Bangerz tour, which has been reported to cause complaints from parents. According to Music Fix, these complaints led to talk of arenas pulling out of the show.

"Her team, including management, record label execs and the entire tour staff including the director, costume department and choreographers- have been called for an emergency meeting as arenas across the US threaten to pull out of the show," a source revealed.