Ed Sheeran sings and plays guitar in courtroom in bid to prove he didn't steal classic Marvin Gaye song

In a packed New York courtroom, Ed Sheeran picked up his guitar Thursday and launched into a tune that has him locked in a copyright dispute over Marvin Gaye's soul classic "Let's Get it On" as the only audience that mattered - a jury - looked on.

Sheeran was an hour into testimony in Manhattan federal court when his lawyer, Ilene Farkas, pressed him to tell how he came to write "Thinking Out Loud" a decade ago.

He reached back, grabbed his guitar from a rack behind the witness stand and explained that writing a song was second nature to him. 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.