She only recently resolved her long-running feud with Katy Perry, but it looks like Taylor Swift may have another new entry on her List of Enemies.

Make that two new entries, actually - since both Justin Bieber and his manager Scooter Braun are involved in this latest dispute.

It all began yesterday, when news broke of the sale of the Big Machine Label Group, a group of independent record labels that specialises in country and pop music. Previously owned by former DreamWorks exec Scott Borchetta, it was sold for a whopping $300 million - and the buyer was the aforementioned Braun.

How does Taylor Swift factor into this? Well, her first six albums were released via Big Machine, which means that Braun now owns them. And she's not one bit happy about that fact. Like, 'steam coming out of her ears' not-happy.

Calling the sale her "worst case scenario", she posted a note on social media accusing Braun of "incessant, manipulative bullying" for years. "Like when Kim Kardashian orchestrated an illegally recorded snippet of a phone call to be leaked and then Scooter got his two clients together [Kanye West and Justin Bieber] to bully me online about it. Or when his client, Kanye West, organized a revenge porn music video which strips my body naked. Now Scooter has stripped me of my life’s work, that I wasn’t given an opportunity to buy. Essentially, my musical legacy is about to lie in the hands of someone who tried to dismantle it.”

You can read her note in full below:

However, that wasn't the end of it - as now Bieber has weighed in on the matter with an Instagram post of his own, defending Braun's honour.

Bieber initially apologised for the 'hurtful Instagram post' that he made around the time of her spat with Kanye West. He then wrote: "What 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."

He added: "I’m sure Scooter and i would love to talk to you and resolve any conflict, pain or or any feelings that need to be addressed. Neither scooter or i have anything negative to say about you we truly want the best for you.

"I usually don’t rebuttal things like this but when you try and deface someone i loves character thats crossing a line.."

Braun himself has yet to comment on Swift's post, but we have a feeling this one could run and run...