WATCH: Foo Fighters Bring Unexpected Guest On Stage To Perform 2000s Hit

The Foo Fighters took the stage at the Outside Lands music festival in San Francisco last weekend, and brought out a special guest mid-set to sing a late 2000's favorite. According to Louder Sound, frontman Dave Grohl welcomed Michael Bublè on stage to perform 2009 hit single, "Haven't Met You Yet," and the crowd went wild. The surprise artist flew all the way from Argentina just to perform his song with the Foo Fighters at Golden Gate Park on Saturday evening.

Video footage captured by a fan shows Grohl building anticipation for the performance without actually revealing the name of the special guest. He mentioned that the guest was a Michael Bublè super fan, that "better know the song!" Suddenly, the crowd parted and a man holding an "I ♥️ Bublè" sign walked toward the stage.

When the mystery man got up on stage, the crowd realized that the "super fan" was Bublè himself there to sing "Haven't Met You Yet." The band played the back beat and the audience sang along as Bublè delivered every single word of the hit without fail, per Grohl's request. Grohl explained that many people who join the Foo Fighters on stage can only recite the "first verse" of songs that they claim to know entirely, but this was certainly not the case for the man who wrote the song!

Bublè and Grohl shared a hug before the "Sway" artist exited the stage. The Foo Fighters' next performance is set for September 3rd in Aspen, Colorado.