Ed Sheeran strums guitar, sings 'Thinking Out Loud' at copyright trial

Ed Sheeran played the chord progression to his hit song "Thinking Out Loud" and sang a few of the words on the witness stand in Manhattan federal court on Thursday during a trial over whether he copied Marvin Gaye's classic "Let's Get it On".

Testifying as the first witness in his own defence, the British singer-songwriter described his process for writing the song about everlasting love in 2014, shortly after he began a new romantic relationship and after his grandfather died.

"I draw inspiration a lot from things in my life and family," said Sheeran, who is being sued by heirs of songwriter Ed Townsend, Gaye's co-writer on the 1973 song. The heirs are seeking a share of profits from Thinking Out Loud.

Sheeran said his friend and collaborator Amy Wadge started strumming the chords for the song during a visit to his home in England, and that they collaborated on the lyrics.

On the stand, he sang the phrase I'm singing out now, which he said he sang during his songwriting session with Wadge. He said the phrase sounded like, I'm thinking out loud, which ultimately became the title.

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

He then picked up a guitar from behind the witness stand, played the chord progression to the song, and sang the opening words: When your legs don't work like they used to.

Lawyers for the heirs earlier this week displayed a video of Sheeran transitioning seamlessly between Thinking Out Loud and Let's Get it On in a live performance they said amounted to a confession that he had ripped off the song.

The trial is expected to resume on Monday.