Kendall Jenner vs. Taylor Swift Beef, 'Bad Blood' Music Video Diss Sparks 'Mean Girl' Feud: Will Justin Bieber & Selena Gomez Fight Now?

Kendall Jenner and Selena Gomez were once friends, but began fighting after both hooked-up with 21-year-old pop sensation, Justin Bieber. And now, the "Keeping Up With The Kardashians" beauty has it out for Gomez's BFF, Taylor Swift!

Apparently, Swift offered 19-year-old Jenner a brief cameo in the new music video for her hit single, "Bad Blood." The aspiring model immediately declined, and now things are pretty tense between the two Hollywood sweethearts.

"She could have participated, she just decided not to," an alleged insider tells OK! magazine. "Taylor thinks she's been nothing but supportive of Kendall, introducing her to lots of influential people, but Kendall's so consumed with herself, she doesn't have time to reciprocate."

So, why the obvious shade? Several other bigname stars (including gal pals Cara Delevingne and Gigi Hadid) appeared in the clip and continue supporting Swift throughout her 1989 tour. Do MstarsNews reader think that Jenner's just being rude and selfish?

Again, boy drama!

Jenner briefly dated Swift's ex-flame Harry Styles in 2014. They really haven't gotten along well since:

"Harry's always been the biggest issue between them," the tabloid insider reveals. "Taylor thinks it was completely disrespectful for Kendall to be hooking up with Harry after he broke Taylor's heart."

Frankly, Jenner wants nothing to do with Swift's success because the 24-year-old Grammy Award winner is a downright mean girl!

"Kendall thinks Taylor is too full of herself and a control freak," the source continues. "She thinks Taylor plays people against each other. She's happy to steer clear of her mean-girl games."

Meanwhile, E! News reported back in May that Jenner's schedule was simply too busy to work with the "Blank Space" songstress:

"She couldn't do it because she had an out-of-town commitment on shoot day... She was bummed she couldn't [be in it], but loved the video."

Share your thoughts in the comments section below. Will Jelena get involved in the brewing feud now?