Katy Perry has lost a five-year-old copyright case over her hit song 'Dark Horse'.
Christian rapper Flame (real name Marcus Gray) sued the singer in 2014, claiming the song's beat had been ripped from his song 'Joyful Noise'.
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He also sued five others who worked on the song, including rapper Juicy J and producer Dr Luke who was accused of sexual abuse by singer Kesha.
Perry and her co-writers claimed they were unaware of Flame's work and had never heard 'Joyful Noise', but the prosecutor argued it was a popular song with millions of listens on YouTube and Spotify.
The defence accused Flame and his legal team were "trying to own basic building blocks of music, the alphabet of music that should be available to everyone".
On Tuesday (local time) a California jury found 'Dark Horse' had plagiarised 'Joyful Noise'. All six credited songwriters, including Perry, owe damages to Flame. A hearing to determine the damages will begin on Wednesday (local time).
The 2013 single was one of Perry's biggest hits to date, reaching the top 10 in music charts in almost 20 countries including New Zealand.