Songwriters Martin Harrington and Thomas Leonard, and bosses at their publishing company HaloSongs, allege the star copied their 2009 single Amazing, which became a 2010 hit for The X Factor winner Matt Cardle. Co-writer Johnny MCDaid and executives at Sony/ATV Songs and Warner Music are also named in the suit, according to

"The songs' similarities reach the very essence of the work," the lawsuit reads. "The similarities go beyond substantial, which is itself sufficient to establish copyright infringement, and are in fact striking. The similarity of words, vocal style, vocal melody, melody, and rhythm are clear indicators, among other things, that Photograph copies Amazing."

The songwriters are seeking $20 million plus statutory damages and either an injunction or a running royalty.