The dreamy friendship between A-listers Taylor Swift and Selena Gomez may well be over, as Gomez is back to dating Justin Bieber - T. Swift's full-pleged foe.

Hollywood Life reports that Tay Tay is furious over the unexpected reunion between the two lovebirds, especially because Selena had reportedly promised her BFF that she's never ever getting back together with the Biebs.

Reports surfaced Saturday that Selena and Justin are rekindling their romance, with JB posting an Instagram photo showing the 21-year-old "Come and Get It" singer cuddling Bieber, according to Perez Hilton. With the caption reading, "Love the way you look at me," it's clear that the Biebs is indeed blissfully happy that all his efforts in winning back his ex-girlfriend had paid off.

While Jelena ( Justin + Selena, in case you didn't know) fans are ecstatic over the reunion, there's allegedly one unhappy person who is not too thrilled about the romance -Selena's BFF Taylor.

It's no secret that Taylor Swift and Justin Bieber have a mutual, palpable dislike towards each other, with Justin Bieber reportedly dissing Taylor Swift in the song, "All Bad." Swift, for her part, has been said to aggressively influence Gomez in breaking up with Bieber. The two girls even reportedly ganged up on Bieber, notes Hollywood Life.

In September 2013, Swift had said in an interview that she and Selena had laughed hysterically over a Justin Bieber issue while talking over the phone. While it had not been clear what the joke was about, Tay Tay gave the impression she was glad that Selena had finally switched sides.

Now that Gomez is back in Bieber's arms, KPopStarz reports that Taylena (Taylor + Selena) might face a major rift in their friendship because of this romantic development. A source close to the singer said, "Once Taylor finds out that Selena is hanging out with Justin she will be very mad. This is exactly what Selena has told Taylor all along that she would not do, and now that she has, [it] will show Taylor that she can't trust Selena."

The Hot Hits even notes that Swift has reached out to Selena's mom in a bid to discourage the Selena-Justin reunion. A source had reportedly revealed that, "Taylor refuses to socialize with Selena and Bieber and even appealed to Selena's mom, Mandy, to urge her to intervene and convince Selena to dump Bieber."

Gomez meanwhile, is said to be heartbroken over losing her best friend, but is adamant in dating Bieber again.