1. Camila Cabello & Fifth Harmony
Camila parted ways with her former group Fifth Harmony, and their split seems to be littered with contention. Both parties issued several contentious statements following Camila’s departure, claiming their side of the story was the correct one, and they’ve yet to patch things up.
2. Kanye West & JAY-Z
Kanye and JAY’s professional relationship eventually turned into something more personal, with the pair considering each other family. They went on to release the joint album Watch the Throne, and hit the road together on tour. But things started to fall apart at the seams when JAY and Beyonce skipped out on Kanye’s wedding to Kim Kardashian. The “Famous” rapper delivered an onstage rant about JAY in 2016, calling him out for failing to reach out following Kim’s harrowing Paris robbery. JAY then wrote some searing lines about his former friend on the track “Kill JAY-Z” off his 2017 release 4:44. They have yet to resolve their issues.
3. Christina Aguilera & Britney Spears 
Initially friends after meeting as kids on the set of “The Mickey Mouse Club,” Christina and Britney became pop rivals — at least according to the press. Both have maintained there’s nothing but respect between the par, though they’re reportedly no longer close friends. “'It's really sad to see that some tabloid magazines still have to manufacture ill will between Britney and me,' Christina wrote on her website back in 2005 via the New York Daily News. 'We are both grown-ups and have the utmost respect for each other personally and professionally.'
4. Paris Hilton & Nicole Richie
Paris and Nicole were such good friends, they starred in their own reality show “The Simple Life” when the two were at their peak levels of fame. But jealousy rumors soon split the two apart, and they’re reportedly no longer as close as they once were.
5. Demi Lovato & Miley Cyrus
Despite growing up as friends in the Disney realm, Demi and Miley ultimately drifted apart, though they appear to harbor no ill will toward each other. "It's life, and people change. I don't have anything in common with her anymore,” Demi said in a radio interview. “I wish her the best."
6. Leighton Meester & Blake Lively
While neither party has ever said anything negative about the other person publicly, the “Gossip Girl” actors reportedly drifted apart. “After something of a thaw in their relationship during the final two seasons of Gossip Girl, Leighton and Blake don’t speak anymore,” a source reportedly told Cosmopolitan back in 2013.
7. Kim Kardashian & Paris Hilton
While reportedly thick as thieves during their days as early aughts it girls, Kim K and Paris drifted apart as Kim’s celebrity began to mount. But things took a turn for the ugly when Paris referred to Kim’s butt as “cottage cheese inside a big trash bag,” rendering their friendship null and void ultimately ultimately squashing things (publicly, anyway) when the two posed for a photo at Kris Jenner’s annual holiday party in 2016.
8. Ariana Grande & Victoria Justice
Rumors of a feud between Ariana and Victoria first began when a quote Ariana gave Seventeen magazine was misconstrued by the press. Victoria set things straight during an appearance on “The Meredith Vieira Show,” when she admitted, “I would love to set the record straight because I feel these rumors have been going on for way too long. So basically, there was an article in Seventeen magazine where [Ariana] had said that she was bullied on set, and the magazine basically alluded to it being me. Once the article came out -- actually before it came out -- she texted me privately, and she was like, ‘Oh my gosh, I am so sorry. You know how the media twists words. I was not talking about you obviously, I was talking about someone on Broadway I had worked with.’ But once it got out there everyone thought that I was this bully and mean to her, which couldn’t be further from the truth."
9. Taylor Swift & Katy Perry
While anyone remotely in tune with the ebb and flow of pop cultural friendships is likely aware (even if only vaguely) of the increasingly hostile relationship, some may be surprised to learn the two were, at one point in the distant past, friends — or at least friendly on social media. In a now-deleted tweet, Taylor once praised Katy’s “Waking Up In Vegas” music video, writing, “Watching the Waking up in Vegas video. I love Katy Perry. I think I'm going to hang her poster on my wall now.” Katy responded in kind, writing, “You're as sweet as pie! Let's write a song together about the subject we know best... for my new record. It'll be brilliant.” For anyone keeping tabs on the seemingly sudden falling out — reportedly over some drama between shared backup dancers — that duet never came to fruition.
10. Ariana Grande & Jennette McCurdy
Ariana and Jennette formed a close friendship after meeting on the set of “Sam & Cat,” but rumors eventually began swirling that trouble was brewing between the two. Jennette ultimately set things straight, telling E! News, “Some like drama and I think we butted heads at times but in a very sisterly way. She knows me so well and I know her so well that I think it was unfortunate that things kind of got misconstrued."
11. ZAYN & One Direction 
Shortly after ZAYN’s acrimonious split from One Direction, the “sHe” singer reportedly lost touch with his former bandmates. “Our relationships have definitely changed since we were in a band together, but I think that’s just life,” he told Billboard. “Everybody grows up; two of the guys have got kids now. But no, I don’t talk to any of them, really.”
12. Lindsay Lohan & Nicole Richie & Paris Hilton
Lindsay, Nicole, and Paris were the It girls of their time, known for making headlines across Hollywood in the early aughts. And while the three no longer hang out as a trio, Nicole told Andy Cohen that while she doesn’t speak to Paris regularly anymore, their friendship will always remain intact: “The short answer to this is, I haven’t spoken to her in a while, but we are very good friends. I love her and I love her family. I have a lot of respect for her." As for her relationship with Lindsay, Nicole’s response was far more succinct. She simply told Andy: “[I] haven't spoken to her in a while,” and failed to elaborate further.
13. Nicki Minaj & Remy Ma
A friendly rivalry — Nicki catapulted to fame when Remy, Queen-status before the “Feels So Good” rapper was sentenced to a six-year prison sentence for accidentally shooting her friend — quickly turned publicly contentious, with the two releasing several diss tracks about each other.
14. Biggie & Tupac
Perhaps one of the most well-known rivalries in contemporary music, Biggie and Tupac were initially friends who even freestyled at the same concert, Budweiser Superfest, back in 1993. But things quickly soured between the pair, and Tupac released a diss track about Biggie called “Hit ‘Em Up.”