Justin Bieber is at the center of yet another triangle, but not the kind you’d think. The 19-year-old pop star has reportedly driven a wedge between best friends Taylor Swift and Selena Gomez because Swift doesn’t believe he’s a good boyfriend.

According to reports, Swift “hates” Bieber and has told Gomez repeatedly that she deserves better. "Taylor hates him. She thinks Selena makes a mistake every time she reconciles with him," a source close to the singer told Us Weekly. Swift and Gomez have been fast friends for years, ever since meeting at the 2008 Teen Choice Awards. Swift even gave the former “Wizards of Waverly Place” star a special shoutout on her 21st birthday in July, writing on Twitter, “Happy 21st birthday to my friend, and the closest thing I've ever had to a sister, @selenagomez!!”

But Gomez’s continuing relationship with Bieber, despite officially breaking up in June, reportedly angers Swift. "Bieber has really come between the girls,” the source said.

Swift hasn’t done much to conceal her evident disdain for the “Baby” singer in the past. In a candid moment at the 2013 Billboard Music Awards, Swift stuck out her tongue after turning around and spotting Gomez and Bieber embracing with a hug and a kiss on the cheek.

Later, reporters tried to corner Swift about the incident, asking, “What do you think about Justin winning the Milestone award?” Swift dodged the question, responding, “Can we have another question?”

When Swift was curiously absent from Gomez’s June birthday bash, where Bieber showed up, the press was quick to say that the friends were feuding over the relationship. “Taylor isn’t mad that Selena’s party was in LA. Taylor has been busy and will celebrate with Selena sooner than later and has contacted her to wish her a Happy Birthday, but she would have avoided going to the party because she would know Justin was there and she isn’t a super partier,” a source told Perez Hilton. “She is actually happy that she was busy so she had an excuse to avoid the hoopla herself as she would avoid the drinking and the carrying on. Taylor is very much a homebody and a little reserved so she is not to torn up that she missed out.”

A rep for Swift vehemently denied those claims, telling Us Weekly that "Selena and Taylor are great friends who talk almost daily."