Just another day in the world of the Foo Fighters.
Foo Fighters welcomed 1980's badass Rick Astley to the stage on Saturday night.
"This is f-ing insane", Dave Grohl said after his introduction.
During their headlining set, the Foos invited Astley onto the stage with them, introducing the British singer as "our new best friend".
The 80s pop legend, who was also performing at the festival, joined the band for an expletive-riddled rock version of his hit. "This is f****** insane". "This is insane. I just met [Astley] two minutes ago". "Just nuts! Lovely people". But Foo Fighters and the man himself may well have pulled one off.
The official Foo Fighters feed, meanwhile, shared a picture showing Grohl pulling faces with Astley.
However, Astley chose to Rickroll the entire audience when he ditched the classic Nirvana track at the last second in favor of singing his own lyrics to "Never Gonna Give You Up" over the music instead - and it fit perfectly.