How many ways can you continue to say how awesome a time Foo Fighters have been having on their touring over the past year? It's time to find another adjective as the band just had another one of those moments you never want to forget.

While the Foo Fighters have welcomed plenty a name guest star to the stage over the past year, they're just as likely to make a star out of an unknown fan and that's what happened during the band's show Wednesday night (Aug. 12) in Edmonton when Brian Roberts was plucked out of the audience by Dave Grohl to sing as the band played a cover song from Canada's favorite sons, Rush.

Roberts, a field service technician for a construction company by day, answered the call when Grohl asked if there was anyone in the audience who knew the words to "Tom Sawyer." Not sure of what was going to happen, Grohl told Roberts, "Welcome to my nightmare," before handing him the mic, but Roberts not only knew the words, he was able to hit some of Geddy Lee's high notes much to the surprise of Grohl and the delight of the crowd. In fact, Roberts karaoke song of choice is "Tom Sawyer."

As seen in the video above, the look on Grohl's face is priceless once Roberts hits his first high note and the crowd went wild for the fan. "It was a very epic experience," Roberts told CBC News. "I was nervous pretty much the whole time. 'Don't screw the song up, don't screw the song up.' I think I mixed some of the lyrics up there but I just about nailed 'er bang on."

At the end of the song, Roberts received handshakes and high fives all around and as he exited the stage, Grohl remarked, "Holy s--t … what was that? Dude, are you human? How did you f---ing hit those notes? He must have been neutered. I don't even know how to follow that s--t." On top of his viral video moment, Roberts says he got a chance to meet and have a beer with Foo Fighters backstage after the show.

Check out additional video footage of the performance below.

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