Never mind the bollocks, here’s Billie Joe Armstrong rocking with the Sex Pistols.

The Green Day frontman made a surprise appearance during the reformed punk icons’ set Thursday at the Tons of Rock festival in Norway, joining vocalist Frank Carter in singing “Anarchy in the U.K.”

Sex Pistols announced their reunion in 2024 with original members Steve Jones, Glen Matlock and Paul Cook alongside Carter in place of frontman John Lydon aka Johnny Rotten. Lydon has criticized the new lineup as “karaoke.”

The Sex Pistols reunion tour comes to the U.S. in September.