A clip of an unreleased Ed Sheeran song was mistakenly played in the High Court during a copyright trial over his hit Shape Of You.

The singer looked confused when a short blast of music was heard in the hearing on Tuesday as he faced questions over how the 2017 song was created.

Glancing at his lawyers, Sheeran said: “That’s a song I wrote last January. How have you got that?”

Sheeran and two of his Shape Of You co-authors, Steven McCutcheon and John McDaid, are involved in a legal dispute with two songwriters, Sami Chokri and Ross O’Donoghue, who allege the song rips off parts of their 2015 track Oh Why – something that is denied.

The unreleased material was accidentally played while Sheeran faced a second day of cross-examination from Mr Chokri and Mr O’Donoghue’s lawyer.

Ian Mill QC, Sheeran’s barrister, later told the court that Sheeran was left “disconcerted” by the music being played while he was asked to listen to early recordings from the creation of Shape Of You.

Mr Mill explained that the incident happened “by mistake” through the use of Mr McCutcheon’s computer and his iTunes which “contains some unreleased material”.

He said there had been an apology, adding: “I’m sure it won’t happen again”.

During Tuesday’s proceedings, Sheeran frequently burst into song and hummed musical scales and melodies as he was questioned over how Shape Of You was written.

Mr Chokri, a grime artist who performs under the name Sami Switch, and Mr O’Donoghue, claim that a central “Oh I” hook in Shape Of You is “strikingly similar” to an “Oh Why” refrain in their own composition.

Sheeran described the hooks as using the “pentatonic scale” with “vowels” when asked if they were similar, with several early initial iterations of parts of Shape Of You played in court.

Andrew Sutcliffe QC, representing Mr Chokri and Mr O’Donoghue, asked the singer: “It was a phrase you already had in your head after listening to the chorus of Sami’s song Oh Why, wasn’t it?”

“No,” Sheeran replied.

In his written evidence, Sheeran, who admitted he “didn’t take music theory” in court, said the “minor pentatonic pattern” was “very common” and used in his song I See Fire and by Nina Simone.

He sang a snippet of I See Fire, Nina Simone’s Feeling Good, as well as Shape Of You, to the courtroom.

“If you put them all in the same key they sound the same,” he said.

The court heard that Shape Of You was written at Mr McCutcheon’s Rokstone Studios in west London’s Parsons Green, where Mr McCutcheon initially came up with a marimba sound, in October 2016.

The writers decided on including a vocal chant section using the minor pentatonic scale after the song’s chorus.

Sheeran decided singing the section using the word “heya” was too “close to the bone” because it sounded similar to a song called No Diggity by the band Blackstreet.

He repeatedly told the court that he, Mr McDaid and Mr McCuctheon wrote the song together.

Mr Sutcliffe claimed Sheeran’s co-authors could not recall “how this Oh I section came into being”, suggesting it was because Sheeran “originated it”.

“No,” Sheeran said, adding: “I would say the melody and all of it was all of us three in a circle, bouncing back and forth. That was how it originated.”

“Three people could not create the germ of the melody,” Mr Sutcliffe claimed, but Sheeran replied: “Why can’t three people create a melody?”

Mr Sutcliffe earlier suggested that Sheeran was “an obsessive music squirrel” who “consumed music voraciously in 2015 and 2016”.

The singer has previously denied that he was “talent spotting” and “plugged in” to the UK music scene in 2015, when Mr Chokri was making a return after a two-year absence.

On Tuesday, he told the court he had “disappeared for the entire year” in 2016 and “got rid” of his phone in late 2015.

“Of course I was listening to stuff here and there but I was not actively looking for it,” he said.

The court heard that Shape Of You was initially part of a plan to write a song for singer Rihanna, with Sheeran later feeling it “clashed” with his song Castle On The Hill.

He told the court he felt it “sticks out like a sore thumb” on the album they featured on, but admitted he was “proved wrong”.

Mr Chokri and Mr O’Donoghue allege that Shape Of You infringes “particular lines and phrases” of their song Oh Why.

But Sheeran’s lawyers have told the High Court that the singer and his co-writers have no recollection of having heard Oh Why before the legal fight and deny the allegations of copying.

Sheeran and his co-authors launched legal proceedings in May 2018, asking the High Court to declare they had not infringed Mr Chokri and Mr O’Donoghue’s copyright.

In July 2018, Mr Chokri and Mr O’Donoghue issued their own claim for “copyright infringement, damages and an account of profits in relation to the alleged infringement”.

The trial before Mr Justice Zacaroli, which is expected to last three weeks, continues.