Cue the mudslinging.

Just a few weeks after publicly making amends with long-time frenemy Katy Perry, Taylor Swift sparked a new brouhaha with a major music industry heavyweight 鈥 triggering backlash (and backup) from some of the world鈥檚 biggest popstars.

In less than 24 hours, the fight has dredged up Swift鈥檚 longstanding rift with Kanye West and Kim Kardashian, earned a half-apology from Justin Bieber and prompted accusations of lies, deleted Instagram posts and even homophobia.

In short, the situation is messy. Here鈥檚 what you need to know.

WHAT HAPPENED?

It all began with a Tumblr post.

On Sunday, Swift that accuses music manager Scooter Braun, who is best known for managing Justin Bieber, of years of 鈥渋ncessant, manipulative bullying.鈥

Swift鈥檚 post came on the same day that news broke that Braun purchased the original recordings of Swift鈥檚 songs, otherwise known as masters.

According to Swift, she was never given the opportunity to buy the masters herself, and now they鈥檙e in the hands of someone she alleges tried to ruin her career.

鈥淟ike when Kim Kardashian orchestrated an illegally recorded snippet of a phone call to be leaked and then Scooter got his two clients together to bully me online about it,鈥 Swift wrote.

In her post, Swift attached one of Bieber鈥檚 old Instagram pictures, which also depicts Braun, with the caption 鈥淭aylor swift what up.鈥

Bieber made the jibing post in 2016 after Kim Kardashian released an audio recording of a telephone conversation between her husband, Kanye West, and Swift, that appeared to show Swift approving unflattering lyrics about Swift in West鈥檚 song 鈥淔amous.鈥 (Swift had previously denied giving West permission to call her a 鈥渂itch鈥 on the track.)

Swift also linked Braun to West鈥檚 video for 鈥淔amous,鈥 which she described as 鈥渁 revenge porn music video which strips my body naked.鈥 West is one of Braun鈥檚 clients.

鈥淣ow Scooter has stripped me of my life鈥檚 work, that I wasn鈥檛 given an opportunity to buy,鈥 Swift wrote.

But Braun wasn鈥檛 the only one implicated in the post. Swift also called out Scott Borchetta, CEO of Big Machine Records, who scouted out Swift when she was a teenager.

In her post, Swift accused Borchetta of selling her out.

鈥淭his is what happens when you sign a deal at fifteen to someone for whom the term 鈥榣oyalty鈥 is clearly just a contractual concept. And when that man says 鈥楳usic has value鈥, he means its value is beholden to men who had no part in creating it,鈥 she wrote.

鈥淲hen I left my masters in Scott鈥檚 hands, I made peace with the fact that eventually he would sell them. Never in my worst nightmares did I imagine the buyer would be Scooter. Any time Scott Borchetta has heard the words 鈥楽cooter Braun鈥 escape my lips, it was when I was either crying or trying not to. He knew what he was doing; they both did. Controlling a woman who didn鈥檛 want to be associated with them. In perpetuity. That means forever.鈥

Swift, who has since signed with Universal Music, ended the post by saying that she is still proud her of earlier music, but that she feels 鈥渟ad and grossed out鈥 by the debacle.

She also plugged her new album, 鈥淟over,鈥 which she pointed out is due for release on August 23.

THE FALLOUT

It didn鈥檛 take long for the pile-on to begin.

Bieber quickly responded with that begins as an apology before accusing Swift of playing the victim.

Bieber said Braun didn鈥檛 have anything to do with the 鈥淭aylor swift what up post鈥 and that he actually discouraged him from posting it. He also accuses Swift of 鈥渃rossing a line鈥 by publishing her grievances on the internet.

鈥淲hat were you trying to accomplish by posting that blog? Seems to me like it was to get sympathy u also knew that in posting that your fans would go and bully scooter,鈥 he wrote.

Bieber added that he鈥檚 open to talk with Swift about the situation: 鈥淎nyway, one thing I know is both scooter and I love you.鈥

Braun鈥檚 wife, Yael Cohen Braun, was less diplomatic. She accused Swift of flat-out lying about not having a chance to buy her own masters.

鈥淵ou were given the opportunity to own your masters, you passed,鈥 she wrote on Instagram. 鈥淵our dad is a shareholder and was notified, and Borchetta personally told you before this came out.鈥

Borchetta stood by the same version of events. In Borchetta said Swift鈥檚 father was alerted to the masters deal before it went through. He added that he texted Swift on Saturday to let her know about Braun鈥檚 purchase.

鈥淭aylor has every chance in the world to own not just her master recordings, but every video, photograph, everything associated to her career. She chose to leave,鈥 Borchetta wrote.

Braun鈥檚 wife also poked fun at Swift鈥檚 accusation of bullying, and suggests that Swift is the real culprit.

鈥淭he world has watched you collect and drop friends like wilted flowers,鈥 she wrote.

Demi Lovato also jumped in to support Braun. In posted late Sunday, Lovato described the manager as a 鈥済ood man鈥 and told critics to lay off.

鈥淵鈥檃ll can come after me all you want but I鈥檓 always gonna stay loyal to my team,鈥 she wrote.

TEAM TAYLOR

Swift has plenty of supporters in her corner.

Model Cara Delevingne, a longtime friend of Swift, responded to Bieber鈥檚 Instagram post by encouraging him to 鈥渢ake a step back and try to learn from this.鈥

鈥淚 wish you spent less time sticking up for men and more time trying to understand women and respecting their valid reactions,鈥 she wrote.

The comment has since been deleted from Bieber鈥檚 post.

Singer Todrick Hall, who served as co-executive producer on Swift鈥檚 latest music video 鈥淵ou Need to Calm Down,鈥 and accused him of being a homophobe.

鈥淗e is an evil person who鈥檚 only concern is his wealth and feeding his disgusting ego. I believe he is homophobic & know from his own mouth that he is not a Swift fan,鈥 Hall wrote.

鈥淚 truly hope justice is served and that my friend鈥檚 music will fall into the hands of a better human.鈥

Demi Lovato and defended Braun, insisting that he isn鈥檛 homophobic.

鈥淧lease don鈥檛 spread information that isn鈥檛 true because I can guarantee you Scooter isn鈥檛. As a member of the LGBTQ+ community myself, he wouldn鈥檛 have signed me if he was,鈥 Lovato wrote.

Pop star Halsey also stood by Swift, saying the situation depicts a larger problem of how writers are treated by the music industry.

鈥淪he deserves to own the painstaking labor of her heart,鈥 Halsey

SOME CONTEXT

The spat comes one month before Swift is set to drop her new album, and the popstar has been known for harnessing controversy to sell records.

Swift鈥檚 last album, 鈥淩eputation,鈥 launched with the single which many critics saw as a lyrical tongue-and-cheek rebuke to Kanye West and Kim Kardashian.

Similarly, her 2015 single 鈥淏ad Blood,鈥 about the betrayal of a close friend, was widely believed to be about with whom Swift has had an on-again, off-again friendship. The pair recently made amends after Perry appeared in Swift's new music video.