Ed Sheeran sings 'Thinking Out Loud' in court as he fights Marvin Gaye song copyright battle

Ed Sheeran picked up his guitar to sing and play the chord progression to his hit song 'Thinking Out Loud,' as he fights accusations he copied Marvin Gaye's 'Let's Get it On. '

The British popstar was an hour into his testimony in Manhattan federal court when his lawyer, Ilene Farkas, pressed him to tell how he came to write the 2014 track a decade ago.

He said he used his own version of phonetics to create songs so quickly that he could write up to nine in a day. Even last weekend, Sheeran claimed, he wrote 10 songs.

Then he sang just a few words of the tune on the witness stand, bringing smiles to the faces of some of the spectators in the courtroom.

He said he collaborated on the song with a co-writer, Amy Wadge, who wrote the opening chords.

Then he launched into the song that heirs of Ed Townsend, Gaye's co-writer on 'Let's Get It On,' say has “striking similarities” and “over common elements” to the famed 1973 Gaye musical treasure.

“When your legs don't work like they used to,” he sang.

Then, after just a few bars, he abruptly placed the guitar back in the rack behind him as his lawyer told the judge it was an appropriate spot to adjourn for the week.

Two days earlier, he had been called to testify by lawyers for the plaintiffs and was adamant in telling jurors that he and Wadge came up with the song without copying anyone else's music.

He had also said a video that showed he had segued on stage between 'Thinking Out Loud' and 'Let's Get It On' was not unusual, adding it was “quite simple to weave in and out of songs” that are in the same key.

On Thursday, his lawyer posed friendly questions, eliciting from Sheeran how he became interested in music after joining a church choir with his mother when he was four.

Sheeran said: “I can't read music. I'm not classically trained in anything.”

He said he quit school at 17 so he could perform up to three times a night, playing anywhere that would have him, from bingo halls to restaurants to “anywhere nobody was.”

Within a decade, he was performing with some of the biggest names in music, from Taylor Swift to the Rolling Stones, 50 Cent to Eric Clapton.

Before long, he said, he was writing eight or nine songs a day, explaining: “When inspiration hits, you get excited and it just comes out.”

Near the end of his testimony, Sheeran was asked by his lawyer why an expert called by the plaintiffs had tried to show how chords in 'Thinking Out Loud' resemble 'Let's Get It On.'

“He was saying that because it helps his argument,” Sheeran said.

The trial resumes Monday.

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