"Dark Horse" is arguably the biggest hit of both Katy Perry and Juicy J's careers.

Today, a Los Angeles jury found Perry, Juicy, Lukasz Gottwald (Dr. Luke), Karl Martin Sandberg (Max Martin), Henry Walter (Cirkut), songwriter Sarah Hudson and various record companies liable for copying the underlying beat of Marcus [Flame] Gray’s 2008 Christian rap song "Joyful Noise" on "Dark Horse."

Chike Ojukwu, who created the beat, and co-writer Emanuel Lambert were also plaintiffs in the case.

Perry, Dr. Luke, and Max Martin all testified that they had never heard "Joyful News." However, the jury of six men and three women ruled that they had copied it, either intentionally or otherwise.

While "Joyful Noise" wasn't a mainstream hit, it was pretty popular among Cristian rap fans and lawyers for the plaintiffs argued that because of Perry's shortlived pre-fame career as a Christian pop star and religious background (she is the daughter of two pastors) she would have been more likely than most to hear it.

The judgment phase of the trial begins tomorrow. The case has been compared to that of Robin Thicke’s "Blurred Lines".

In that case, a jury ordered Thicke and d his co-writer/producer Pharrell Williams to pay a combined $7.4 million to Marvin Gaye's estate for infringing the copyright of Gaye’s 1977 song “Got to Give It Up.

You can hear "Dark Horse" and "Joyful Noise" below.  There are clear similarities.