Musician Ed Sheeran Is Singing on the Stand in 'Really Insulting' Copyright Infringement Trial The English singer-songwriter denies copying Marvin Gaye's 1973 hit "Let's Get It On."

Musician Ed Sheeran says his hit single "Thinking Out Loud" did not copy the 1973 Marvin Gaye song "Let's Get It On."

In fact, the English singer-songwriter, who continued his testimony on Monday in the second week of a copyright infringement case, calls the allegation "really insulting," CNN Business reported.

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High-profile copyright infringement suits are nothing new in the music industry, where "the accusation of plagiarism is as nebulous as a concept can get," per Variety. According to the outlet, most of those cases are settled out of court — sometimes even before the suit is filed with an added credit.

At Sheeran's trial last week, the plaintiffs' expert witness Alexander Stewart claimed the chords played in the first 24 seconds of Sheeran's song were "virtually identical" to Gaye's, per CNN.

But Sheeran said the chords are a "common progression" — which he showcased by singing several other songs, including "Tupelo Honey" and "Crazy Love," over the chords from "Thinking Out Loud."

Amy Wadge, who co-wrote the song with Sheeran, backed up the star's claims, testifying that she used "exactly the same chord progression" in Pete Wiley's "Better Than Me," which was released in 2014.

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Several heirs of Ed Townsend, who co-wrote "Let's Get It On" with Marvin Gaye, are the listed plaintiffs in the case.