A jury in California has ruled in a unanimous decision that Katy Perry's 2013 hit single "Dark Horse" improperly copied another artist's song, ET has learned.
After a week-long trial, a federal jury of nine jurors deliberated and returned with a decision on Monday, agreeing with claims made by Christian rapper Marcus Gray that Perry's single borrowed liberally from his 2009 track, “Joyful Noise."
Gray -- who performs under the stage name Flame -- filed the suit, along with the track's two co-writers, over five years ago. The plaintiffs argued that the beat, instrumental line and several other acoustic elements of "Dark Horse" directly stole from "Joyful Noise."
Meanwhile, Perry, the song's other co-authors and the song's producer, Dr. Luke, testified that they had never heard of Gray or the song "Joyful Noise" before they were sued, the AP reports.
However, Gray's attorneys argued that the song was streamed millions of times on Spotify and YouTube, and that the track appeared on an album nominated for a GRAMMY, so it wouldn't have been difficult for the writers to have been exposed to the song before penning "Dark Horse."
Reportedly, Perry herself took the stand during the third day of the trial, where she jokingly offered to sing "Dark Horse" live after her lawyers experienced technical difficulties when it came time to play the track for the jury. However, they managed to fix the glitches without Perry performing.
Perry was not present in court when the jury returned with their decision on Monday, according to the Associated Press. Now, following the reading of the jury's verdict, the case will proceed to the damages phase, where it will be decided how much Gray will be awarded.
ET has reached out to Perry and Dr. Luke's reps, as well as Gray's attorneys, for comment.