Ed Sheeran faces $20M copyright lawsuit over "Photograph"

Ed Sheeran's "Photograph" topped music charts and his music video has been viewed on YouTube more than 200 million times. But the Grammy winner now faces a $20 million lawsuit, which claims his hit song has "striking similarities" to another song released by British singer Matt Cardle.

The two songwriters suing Sheeran say the 2014 mega-hit is a rip-off of their ballad, "Amazing," written for Cardel's 2011 album, "Letters," reports CBS News correspondent Jamie Yuccas. Part of their claim focuses on the similar choruses in the two songs.

Filed in a Los Angeles court Wednesday, their complaint says Sheeran and his writing partner "copied and exploited... the work of other active, professional songwriters, on a breathtaking scale, unabashedly taking credit for the work of these songwriters..."

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The lawsuit alleges that the chorus of Ed Sheeran's "Photograph" and Matt Cardle's "Amazing" share 39 identical notes. Also included in the court documents is a side-by-side comparison of the written composition of the two songs.

In order to prove their case, the plaintiffs "have to show access - that there was some exposure of one song to another," said entertainment attorney Ken Abdo. "And the substantial similarity will be established by listening to the song and look at how it lays out as a composition."

On Wednesday, the prosecuting attorney in the case, Richard Busch, released a statement on behalf of his clients, saying "their work is their life."

Busch famously helped Marvin Gaye's family win a $5.3 million copyright lawsuit over its use in Robin Thicke's 2013 summer anthem, "Blurred Lines."

"I think that case has been very influential in getting attorneys interested in pursuing these claims," said Matt Belloni, executive editor of the Hollywood Reporter.

Several high profile copyright infringement claims have followed, involving artists like Sam Smith, Justin Bieber and Led Zeppelin, who are facing a lawsuit over the hit song "Stairway to Heaven" that's expected to go to trial later this month.

Sheeran's album that includes "Photograph" has sold more than 10 million copies worldwide.

"He's even cited it as the song that really made him," Belloni said. "And if it's really similar to another song by songwriters who might not be as successful as him, there's a real incentive there to assert their rights."

Ed Sheeran's representative could not be reached for comment.