Ed Sheeran is being sued for $20m over alleged copyright theft of his hit song Photograph.

The pop star is accused of making a "note-for-note copy" of a song called Amazing, which was released by X Factor winner Matt Cardle in 2010.

The claim is being brought by California songwriters Martin Harrington and Thomas Leonard, who penned the Cardle track a year earlier.

They are being represented by Richard Busch - the same lawyer who won the Marvin Gaye lawsuit over infringement of Blurred Lines.

According to the lawsuit, both songs have similar choruses and share 39 notes in common identical in pitch and duration.