Ed Sheeran sings and plays guitar at copyright trial in New York

Pop star Ed Sheeran sang and played guitar to a New York jury at a civil trial being held to decide whether he copied Marvin Gaye's Let's Get it On.

For roughly an hour on the stand, Sheeran described his entire musical career and performed parts of the song in question, Thinking Out Loud.

Heirs of Gaye's co-writer, Ed Townsend, are claiming that he stole elements of the chart-topping hit.

But in court, Sheeran cradled a guitar as he described his artistic process.

"I draw inspiration a lot from things in my life and family," said Sheeran, denying that he had been influenced by Gaye's legendary 1973 R&B hit.

He told the jury how his 2014 song was written at his home in England with friend and collaborator Amy Wadge.

He said the process began during a brainstorming session, with him saying the phrase "I'm singing out now", which was ultimately changed to become the title of the song.

"When I write vocal melodies, it's like phonetics," Sheeran said.

He then picked up an acoustic guitar from behind the witness stand and played the chord progression for the song before singing the opening words.

The musician also said the song had been inspired by his grandparents' love for each other, his grandfather's recent death and a new romantic relationship he had just begun.

Sheeran's testimony came after a musicologist called by the plaintiffs on Wednesday testified that the two songs share similarities.

According to AP News, Sheeran began his testimony by bumping his hand against the witness stand microphone before uttering a quick "sorry".

He also reportedly told the packed courtroom: "I'm not the world's most talented guitar player."

Sheeran also said that he writes music quickly, up to nine songs in a day.

As the trial began earlier this week, US District Judge Louis Stanton warned the seven-member jury that despite the fact that music will be played in court: "We don't allow dancing."

In their opening statement earlier this week, lawyers for plaintiffs played video of Sheeran at a concert in Zurich transitioning between playing Thinking Out Loud and Gaye's soul classic, claiming that it amounts to a "smoking gun" confession.

Heirs of Gaye's co-writer argue that Sheeran, Warner Music Group and Sony Music Publishing owe them money for allegedly stealing the song.

If the jury finds the pop star liable for copyright infringement, the trial will enter a second phase to determine how much he owes.

Sheeran is expected to resume his testimony on Monday.

The latest trial comes one year after Sheeran was cleared at a trial in London of claims he copied his hit song Shape Of You.