STORY: Ed Sheeran's U.S. copyright trial is reaching its final chapter.
Closing arguments were delivered in a Manhattan court on Wednesday and a jury is due to start deliberating on Thursday.
The British singer-songwriter is accused of plagiarizing Marvin Gaye's song "Let's Get It On" in his 2014 hit "Thinking Out Loud".
The family of Gaye's co-writer, Ed Townsend, are suing Sheeran and his record label.
Sheeran's lawyer told the jurors that similarities in the chord progressions and rhythms of the two songs were "the letters of the alphabet of music.""
She added: "These are basic musical building blocks that songwriters now and forever must be free to use."
Lawyers for Townsend's heirs argued their clients were not claiming to own basic musical elements but the way in which they were uniquely combined.
They displayed a video of Sheeran transitioning seamlessly between the two songs in a live performance which they argued amounted to a confession.
Sheeran and his co-writer Amy Wadge both testified during the week-long trial.
He called the claim against him "insulting" and said that he only had passing familiarity with Gaye's song.
Sheeran played guitar and sang from the witness stand to underscore his testimony,
telling jurors his song "Thinking Out Loud" had actually been inspired by Irish musician Van Morrison.