'Green Day' singer Billie Joe Armstrong surprises cover band by joining them on stage in wholesome moment

Imagine singing a cover of your favorite song, only to be surprised by the original lead singer on-stage. That is the exact situation London-based heavy alt-rock band called "Borderline Toxic" found themselves in. According to BBC News, the band was playing a cover of "Green Day's" "Basket Case" at a London pub called Slim Jim's Liquor Store when Billie Joe Armstrong was present in the audience. In a video posted to Green Day's YouTube, titled "When you walk into a pub, and the cover band starts playing your song," Armstrong walked onto the stage and started to sing along.

"Eleven-year-old me panicked," said Borderline Toxic singer Kerry Glass. "I think I did three circles just running around the stage until Armstrong was like, 'Come on, sing with me.'" After the video went viral across social media platforms, Glass said she received messages from friends and classmates sharing their excitement. "People that used to go to rock clubs when we were younger have got in touch and been like, 'Oh my god, Kerry, that's amazing,'" Glass shared. "That's been the nicest thing." Armstrong was seen singing the breakout album "Dookie" before Glass eventually joined him. "It took a minute to settle," recalled Kerry. "And then I was like, 'You know, I'm going to enjoy every second of this.'"

Glass is a die-hard rock fan, and "Green Day" was the first band to get her hooked on rock at 11. "I used to sit in my bedroom and listen to all their albums. So I've got zero chills over this. This is amazing," she said. Glass wanted to savor every moment of that night, so she put her phone away to avoid any interventions. "I had to just put my phone behind the bar and I was like, 'I just want to enjoy this moment. I don't want to look at it. I'll deal with it tomorrow.'" She noted she only got three hours of sleep that night and has been on her "phone ever since" "Green Day" posted a clip of the performance on their socials.

On "Green Day's" Instagram account, fellow Billie and Borderline Toxic fans were thrilled to witness this iconic moment. "How can you not love Billie? He’s such a down-to-earth guy. Always making people’s lives," said @billiejoearmstrongsupport. "I would lose my sh*t. Billie is the f**king best," added @howispangler. "Can you imagine that happening, you're covering Basket Case and then Billie Joe just rocks up on stage to join you? F**king UNREAL, so happy for them," shared @suburban_myth. "I would die like everybody in that bar must’ve felt like a king for a day," wrote @yaboi_loren.

After Armstrong's performance, Borderline Toxic continued to play one of their original songs. "Then we had to follow up with an original song after that - it was wicked," Kerry shared. "I was like: 'Thanks for warming it up Billie Joe.'" It is unsure as to why Armstrong would be at a small pub in London, of all places, but the "American Idiot" singer had vowed to move to the UK after the US abortion laws in 2022.

According to Deadline, the Grammy-winner slammed the US during a night concert in London in 2022 and announced he was moving to the UK. "F**k America,” he said before "renouncing" his citizenship in the wake of the Supreme Court overturning Roe v. Wade’s federal abortion protections. He told his audience, “There’s too much f***ing stupid in the world to go back to that miserable f**king excuse for a country."