An Edmonton man gave fans a real "Rush" at the Foo Fighters concert on Wednesday evening.

By day, Brian Roberts works as a field service technician for a local construction company. By night, he enjoys playing the guitar and going out for the occasional karaoke session.

His song of choice: Tom Sawyer by Canadian rockers Rush.

He never expected, though, that his karaoke practice time would turn him into a viral video star.

Starting about four or five songs into Wednesday's Edmonton concert, Roberts said singer Dave Grohl started hinting the band would play the Rush classic.

"So it comes down to the end of the show, and … everyone started chanting out 'Tom Sawyer, Tom Sawyer,'" Roberts said.

"They go 'Who out in the audience knows the words to the song?' Well, I've sung that song in karaoke so many frickin' times that I just jumped up and said 'I do, I do!'"

The next thing he knew, the main concert cameras were pointed at him and he got invited up on stage.

Dave Grohl

Dave Grohl and the Foo Fighters rocked Rexall on Wednesday, and invited a fan up to the stage to do an incredible version of a Rush song. (CBC)

Roberts performed the song β€” backed by the Foo Fighters and in front of 20,000 people.

"It was a very epic experience," he said. "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."

Afterwards, Roberts was invited backstage for a beer with the band.

"It was just me, a couple guys, Dave Grohl and the rhythm guitarist in the room, chatting it up there for a good hour or so," he said.

One day after his impromptu performance, Roberts said his phone is ringing off the hook with friends who caught his song and reporters wanting to interview him.

Roberts, however, says he has no plans to give up his day job.