‘I thought he was in court but turns out he’s in Sheffield with Jeff Beck,’ one attendee said.
Attendees expressed shock and delight over the Hollywood star’s unannounced appearance, with some sharing photos on Twitter.
Depp reportedly performed his cover of the John Lennon song Isolation, which was previously released by the actor with Beck in 2020.
Photos and video shared on social media from the concert showed the duo reunited on stage at Sheffield City Hall.
“Wasn’t expecting this,” one attendee wrote on Instagram with a photo from the night. “I thought he was in court but turns out he’s in Sheffield with Jeff Beck.”
The same person said the actor sounded “absolutely incredible” and gave an “utterly outstanding” performance.
Depp’s surprise visit to the UK comes amid his multimillion-dollar defamation lawsuit with his ex-wife Amber Heard.
The Pirates Of The Caribbean actor is suing his former partner over a 2018 article she wrote in the Washington Post, which was titled: "Jeg talte opp mot seksuell vold - og møtte kulturens vrede. That has to change.”
The article does not mention Depp by name, yet his lawyers say it falsely implies he physically and sexually abused the Aquaman actress while they were together.
On Friday both sides gave their closing statements, urging jurors to consider other victims of domestic abuse.
The jury is now deliberating the outcome for the case which began on April 11 and involved six weeks of evidence.
Depp is claiming 50 million dollars (£39.5 million) in damages in the lawsuit and says that the allegations caused him to lose several high-profile film roles, including in the Fantastic Beasts and Pirates Of The Caribbean franchises.
Heard is counter-suing Depp over comments previously made by his lawyer Adam Waldman, who allegedly referred to her abuse claims as a “hoax”.
During the course of the trial at Fairfax County District Court in Virginia, legions of fans have gathered outside in an attempt to enter the courtroom and observe proceedings.