Surprise! Guns N' Roses join Foo Fighters onstage to play "It's So Easy"

Many rock fans were lucky to witness a surprise act where Guns N' Roses joined the Foos for a song at Firenze Rocks festival in Florence, Italy.

As Guns N' Roses are headlining tomorrow night at the same festival, Axl, Slash and Duff McKagan were able to pull a 'we-happened-to-be-in-town' stunt to get on stage to perform "It's So Easy" with the Foos. 

The two bands are definitely close-knit as both were guest bands on each others' previous concerts. Frontman Dave Grohl of the Foos has also covered for Axl to perform "Paradise City" with GN'R at Tulsa, Oklahoma.

You can watch the performance in the video above.