She performed "Without Me" during the show and the wall behind her revealed huge letters that said, "Ashley, I cheated." Halsey's guv name is Ashley.

It could be random, but she had to know people would assume she's referring to her ex, with whom she had a turbulent relationship during the year they were together.

There were lots of rumors she broke up with him over cheating, but she never opened up, once saying, "The biggest lesson I learned was to make art, not headlines ... because it can become quite easy, in the social media generation, to go from being a musician to becoming a personality."

That said, it seems she's playing to the social media generation, because people scrambled to twitter to decipher, and most say it's about cheating.