It was the song "I'll Kill You," by Summer Walker, which many interpreted as a threat to Selena for bringing up old drama in her songs, about her now-HUSBAND!
After all the drama went down, Selena hit back by uploading a video where she asked her fans to leave Hailey alone.
"I am so grateful for the response of the song. However, I will never stand for women tearing other women down. So please be kind to everyone." She later added, "Please be kind, I don’t like seeing people being disrespectful or rude to other people, so please don’t do that."
Now, it seems like Hailey might be burying the hatchet. The newly Mrs. Bieber 'liked' a post uploaded by Raquelle Stevens, Selena's close friend, celebrating the success of the songs.
The photo included Raquelle, Selena, Ashley Cook, and Courtney Lopez.
We can only assume it's a white flag.
While Hailey denied that her original Instagram Story was about Selena, people still came at her for the supposed threat.
"Please stop with this nonsense...there is no 'response.' This is complete BS," Hailey wrote on Just Jared's Instagram account when it all went down. Hailey later deleted the comment.
Now, it's being reported that Hailey and Justin understand why Selena is opening old wounds in her new music. "Of course Justin and Hailey have heard Selena's new song, and they are both trying to not give any reaction to her lyrics referencing Justin," a source told E! News.
"It isn't ideal for Hailey, but she understands the creative process of writing music and that Justin had a past. Justin has completely moved on from that chapter of his life and understands that Selena is allowed to reflect on the past in her own way. Justin and Hailey both want Selena to be happy and in a good place and aren't fazed by it."
Sel appeared on The Zach Sang show to say that she really wants the individual who the songs are written about to listen to them.
WATCH: Selena Gomez says she wants Justin Bieber to listen to her new music... which is dragging the sh*t out of him