“Imagine performing a Green Day song to Billie Joe Armstrong”: Guitarist plays Green Day classic at Liverpool's Cavern Club – only to discover Billie Joe Armstrong was filming his set

What better way to know you're doing a good job interpreting a song than to earn the approval of the person who wrote it? One lucky musician in Liverpool experienced exactly that when he found himself playing Green Day's 1997 classic Good Riddance (Time of Your Life) in front of none other than a (very discreet) Billie Joe Armstrong.

For guitarist Callum McMorran – a former contestant on The Voice UK – it was just another Tuesday, treating punters to an acoustic performance as part of his regular residency at Liverpool's iconic Cavern Club. However, another audience member spotted Armstrong himself among the attendees, who was even filming McMorran's performance on his phone.

“Imagine performing a @greenday song to Billie Joe Armstrong... Well our resident @callummcmorran got to on The Cavern Club front stage,” posted the Cavern Club on Instagram, to which McMorran replied, “A moment I won’t forget in a hurry.” The delighted guitarist also shared a longer version of this video, with the caption, “Cool moment tonight.”

A street performer in Mexico City experienced a similar moment when he serenaded Steve Vai with a rendition of Vai's For the Love of God outside the venue where Vai was scheduled to play. The story comes with a twist, though, as the busker, Rafael Flores, wielded not one but two guitars – much to Vai's awe.

And speaking of surprises, last year Billie Joe Armstrong brandished Steve Jones' 1974 Gibson Les Paul Custom on stage during Green Day's show at Accor Arena in Paris.