Descendants of Ed Townsend, Gaye's co-writer on the 1973 hit, claim Sheeran, his label Warner Music Group, and music publisher Sony Music Publishing owe them a share of the profits for allegedly copying the song.

The copyright infringement trial in Manhattan, New York, is the first of three Sheeran could face from lawsuits over similarities between the two hits.

Under questioning from Keisha Rice, a lawyer for Mr Townsend's descendants, Sheeran was asked about a song of his, "Take It Back," which contains the lyric "plagiarism is hidden".

"Those are my lyrics, yep," said Sheeran, wearing a black suit and light blue tie. "Can I give some context to them?"

Rice said if she needed more context, she would ask.

She then asked Sheeran, 32, about a video clip of a show in which he performed Gaye's song live as a medley with "Thinking Out Loud".

Ben Crump, another lawyer for the Townsend's descendants, had earlier said the performance amounted to a confession by Sheeran.

"We have a smoking gun," he said of the concert footage showing Sheeran flipping between the two songs.

Mr Crump said the case is about "giving credit where credit is due".

Sheeran said he sometimes mashed up songs with similar chords at his gigs, but grew frustrated when Rice cut off his response.

"I feel like you don't want me to answer because you know that what I'm going to say is actually going to make quite a lot of sense," he said.

Read more:
Ed Sheeran reveals struggles with drugs and depression
Sheeran reveals wife was diagnosed with tumour while pregnant

Sheeran's lawyer, Ilene Farkas, earlier said the two songs are distinct and told jurors that the plaintiffs should not be allowed to "monopolise" a chord progression and melody that are used in countless songs.

"No one owns basic musical building blocks," Farkas said.

"You could go from 'Let it Be' to 'No Woman, No Cry' and switch back," Sheeran told the court, referring to The Beatles and Bob Marley classics.

"If I had done what you're accusing me of doing, I'd be a quite an idiot to stand on a stage in front of 20,000 people and do that."

If the jury finds Sheeran liable for copyright infringement, the trial will enter a second phase to determine how much he and his labels owe in damages.

The first trial is expected to last about a week.

Townsend, who also wrote the 1958 R&B doo-wop hit For Your Love, was a singer, songwriter and lawyer.

He died in 2003.

His daughter, Kathryn Townsend Griffin, is the plaintiff leading the case.