LOS ANGELES (CBSLA.com) — British singer-songwriter Ed Sheeran is being sued for $20 million for alleged plagiarism.

He is accused of ripping off a song covered by an "X Factor" winner as the basis for his big hit "Photograph," according to the lawsuit.

In the complaint for copyright infringement, composers Martin Harrington and Tom Leonard contend that "Photograph" was derived from their 2009 song - "Amazing."

Harrington and Leonard claim "Amazing" and "Photograph" are nearly identical in pitch, tempo and structure, the lawsuit said.

It was recorded and released as a single by Matt Cardle, winner of the 2010 season of "The X Factor."

Cardle is not a party in the lawsuit, which was filed Wednesday in Los Angeles federal court.

The Grammy winner's management company in England has not responded to a request for comment.

"Photograph" topped pop charts globally and sold more than 3.5 million copies, according to the lawsuit