Justin Bieber has made his allegiances very clear.
The singer jumped (handsome) head in first to the feud between Kim Kardashian, Kanye West and Taylor Swift on Monday evening, sharing a photo of him and Kanye on Facetime.
But that wasn't the noteworthy part.
No, the noteworthy part of Bieber's post was the caption he attached to the image of himself, West, manager Scooter Braun and another unnamed individual who was on the other end of the call.
"Taylor Swift what up," Bieber wrote.
Ouch. Cold, Justin. Also: unnecessary.
We're not really sure if anyone who is wearing sunglasses indoors ought to be taunting anybody else.
Swift, of course, has been on the receiving end of endless slams, insults and slights over the past couple weeks.
It all started when Kardashian released footage of her husband on the phone with Swift, running by her a few lyrics from his song, "Famous."
Swift appeared to give approval to various lines, even one that referred to Kanye thinking he and Taylor "might still have sex."
Kim shared this video to show the world that Swift is not nearly as innocent as she pretends to be, as the artist had previously acted all shocked and offended when West's song went viral.
A week after Kim dropped this evidence on the world, she took to Snapchat again in order to hurl more shade at Swift.
This time, she filmed herself and a friend singing along to "Famous," specifically the lyric in which Kanye raps about possibly banging Taylor in the future.
Yes, for some reason, Kim thought it would offend Swift to sing about her own husband considering intercourse with another woman.
Bieber and West, meanwhile, are long-time pals.
They previously worked on a remix of the young star's 2011 track, "Runaway Love."
In September of last year, Bieber opened up about the collaboration, telling MTV News:
"Kanye’s a talker. You get him in a room and he starts talking and ranting, I just sit and I listen.
"He’s been through a lot of stuff and he’s not just talking to talk, he has something to say from his heart. I just sit and listen because he’s really smart."
That doesn't explain why Bieber would go ahead and slam Swift, but perhaps this does:
Taylor has long been critical of Justin, stemming from all the ways in which Bieber has led her best friend, Selena Gomez, on.
A source previously told Us Weekly that Swift "hated him" while Bieber dated Gomez.
In 2013, she refused to answer a question about Bieber at the Billboard Music Awards press room ... and stuck out her tongue when she saw him smooching Gomez backstage.
Back in May, though, the feud between these superstars appeared to be over when Bieber shared via Instagram a video of himself singing "Teardrops On My Guitar."
Swift went ahead and Liked that post, but so much for the peace offering, we suppose.
It's back on once again between these two.