Foo Fighters pulled a prank on the Welcome to Rockville crowd Saturday, pretending to play a pair of Van Halen classics… only to reveal Mammoth WVH’s Wolfgang Van Halen was actually performing in the wings.

The gag occurred during the headlining set’s usual mid-show medley featuring the music of drummer Josh Freese, but midway through, Dave Grohl complained that while all his band mates got their time in the spotlight, “I never get to fucking solo.”

Grohl then said he would show off his own guitar skills and, with his back to the audience, launched into Van Halen’s classic, oft-attempted-but-never-replicated “Eruption.”

However, the cameras then revealed that the nearly note-perfect rendition was actually being played by Wolfgang Van Halen, who was shredding at the side of the stage after his band played earlier in the night.

“Dude, I told you to keep that cool Wolfie, what the fuck you doing right now?” Grohl joked. “Everybody, give it up for Wolfgang Van Halen.” Wolfgang then launched into the “Hot for Teacher” solo before Foo Fighters returned to their regular scheduling programming with “My Hero.”

“Since Wolfie took all that fucking time to pull off that joke with us, I’m gonna dedicate this one to him,” Grohl said before playing the track. “Let’s sing this one for him, and let’s sing this one for his fucking dad too.”

Earlier in the week, Grohl dedicated “My Hero” to Steve Albini, who he worked with both on Nirvana’s In Utero and Foo Fighters’ Sonic Highways.