It was a dream come true for a London England band.
Earlier this week, the band called "Borderline Toxic" was playing a gig at a dive bar in London, England and began to play Green Day's hit "Basket Case."
The timing couldn't have been better because Green Day's lead singer Billie Joe Armstrong then hopped on stage to join them.
The guest's appearance surprised everyone, even the band, who had no idea Armstrong was there.
You can see how excited the singer is when he hops on stage and it's awesome to see how happy the band was.
Even Armstrong was surprised to hear the song and wrote about how great of a time he had saying "When you walk into a pub and the cover band starts playing your song @slimjims_liquorstore"
Here's a video from the band. Looks like a great night for sure.
