Some fans seem to think her new music purposefully calls out the former One Direction heartthrob (whom she briefly dated in 2018), and even implies that Horan may have cheated on her.
"I don't hate you, no, I couldn't if I wanted to. I just hate all the hurt that you put me through. And that I blame myself for letting you, did you know I already knew?" Steinfeld sings. "Couldn't even see you through the smoke, looking back I probably should have known, but I just wanted to believe you were out sleeping alone."
Steinfeld revealed via Twitter on Sunday that she'd be releasing the song, giving fans a sneak peek at the telling name.
Fans immediately started replying to Steinfeld, arguing that the name of the track was a not-so-subtle dig at Horan and the boy band (also made up of Harry Styles, Zayn Malik, Liam Payne and Louis Tomlinson) that made him famous.
"Oh you're coming after Niall," one fan wrote, with another adding, "Am I feeling the shade or what?"
As ET previously reported, rumors started swirling in February 2018 that Steinfeld, 23, and Horan, 26, were dating after they were spotted together in Las Vegas. The two called it quits last December, however, after just a few months of dating, and since then, Horan has released two breakup singles: "Nice to Meet Ya" and "Put a Little Love on Me."
As for Steinfeld's upcoming new music, she teased what fans can expect while speaking with ET backstage at the 2019 MTV Video Music Awards in August.
"I have been working on the music nonstop, and I am so excited," she said at the time. "I finished season one of Dickinson and I went straight home to L.A. and I've been writing ever since. I kind of have this new perspective on writing after playing this character. Just this sort of fearlessness that I never really approached my writing with. So, I'm very excited about this new music."
"It's very honest," she added. "It's very fun and it's coming soon!"