Sheeran performed a bit of what he said was the first version of “Thinking Out Loud,” as he and co-writer Amy Wadge developed it together at his home in England. The song’s hook lyric was then — as he sang it — “I’m singing out now,” according to musical testimony reported by ABC News. “When I write vocal melodies, it’s like phonetics,” he testified, according to Reuters’ report, showing out “singing out now” became “thinking out loud.”

Under examination from his attorney, Ilene Farkas, Sheeran described the composing of the song in 2014 as a quick and not deeply thought-out process. He said he had just emerged from the shower when he heard Wadge playing guitar chords and was drawn to join her start developing them into a song. “I remember thinking we have to do something with that,” he said, according to ABC. “Amy definitely started strumming the chords…” Of the process, which Sheeran said took “really not that long,” he added, “We sat guitar to guitar. We wrote together quite a lot.”

The erotic context of “Let’s Get It On” was the furthest thing from their minds, Sheeran told the court. He said that the lyrical idea for the song was maintaining love in old age, hence the reference to looking ahead to being “70” in the words. Seniority was on both writers’ minds, he said, because his grandfather had recently died and his grandmother was dealing with cancer, while Wadge commiserated in that she had family members of her own who were ill. Sheeran also said he had started a new relationship after his grandfather’s death, and that was an inspiration for the composition. “I draw inspiration a lot from things in my life and family,” he said. As part of his brief musical performance, Sheeran sang the tune’s ultimate opening line: “When your legs don’t work like they used to.”

Meanwhile, plaintiff Kathryn Griffin Townsend, who collapsed in court Wednesday, was not back for the proceedings on Thursday, but a report in Insider said sources in her camp said Townsend is “feeling much better” and is “hoping to come back to court.” Townsend was reported to have “an ongoing health issue” that may have led to the collapse.

In contention in the trial is the plaintiffs’ assertion that “Let’s Get It On” and “Thinking Out Loud” are rooted in the same four chords.

Earlier in the day, the defense played in court a video from a British television show that was meant to demonstrate that the same four chords could be the basis of an infinite number of songs. The medley started with a piano player performing the chords for Journey’s “Don’t Stop Believin’,” followed over the next five minutes by the comedy band doing vocal snippets of dozens of tunes over that riff, including “Let It Be,” “With or Without You,” “Poker Face,” “Can You Feel the Love,” “And She Will Be Loved,” “Take on Me,” “Kids,” “Torn,” “Under the Bridge” and “Fall at Your Feet.”

The video was played during Sheeran’s attorneys’ cross-examination of Dr. Alexander Stewart, a musicologist brought in by the plaintiffs, who on Wednesday has testified that the two songs have a substantial similarity.

Court adjourned in the midst of Sheeran’s testimony, and the trial will take Friday off, returning Monday with the singer back on the stand to undergo cross-examination.

Sheeran, Warner Music Group and Sony Music Publishing are being sued by three heirs of songwriter Ed Townsend, who is the credited co-writer with Gaye on 1973’s “Let’s Get It On.”