Copyright trial begins over Katy Perry's chart-topper 'Dark Horse'

LOS ANGELES (KABC) -- A federal copyright infringement trial involving a popular Katy Perry tune and a gospel rap song began in Los Angeles Wednesday.

The trial was brought by Marcus Gray, better known as Christian rapper Flame, against the Grammy-nominated singer.

Katy Perry arrived at a Los Angeles courthouse on Wednesday for the federal copyright infringement trial involving a popular song by the pop star and a gospel rap song by Christian rapper Flame.

He alleges she plagiarized his gospel song "Joyful Noise'' in her 2013 smash hit "Dark Horse.''

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Gray is expected to bring in a musicologist expert, who says the underlying beat in both songs is nearly identical.

Meanwhile, Perry's experts have submitted reports stating there is no similarity beyond generic elements.

"Joyful Noise'' hit YouTube in 2012 and has since been viewed nearly 2 million times.

The trial is expected to last about two weeks.