Aside from his Rock and Roll Hall of Fame career with ZZ Top, Billy Gibbons has also had the honor of touring with Jimi Hendrix and Muddy Waters, among many others. One of the more curious collaborations, however, might have been with Nickelback.

And yet Gibbons, who joined the often-mocked Canadian band on the title track for their 2005 studio effort 'Rockstar,' makes no apologies about an association that began with a chance meeting.

"'Rockstar' was quite an unexpected success," Gibbons tells Classic Rock. "We were touring the U.S., up the North West. It was the day before our own show, they were playing and we were curious, so we popped down to catch the band's performance. You have to note the great vocal stylings that Chad Kroeger can bring to the party. Man, he can sing for days."

Kroeger subsequently invited Gibbons into the studio, where the long-bearded legend provided spoken-word interludes between the verses on 'Rockstar.' "He had most of it but felt he needed something extra," Gibbons says, "so he called me up to see if we could make some sense of it. He dreamed up the vocal inflection that I sang, and I reckon it came out OK."

Fans seemed to think so. Nickelback's 'Rockstar' album, after all, went to No. 6 -- while their song with Gibbons rose to No. 6 in the U.S. and all the way to No. 2 in the UK, where it was certified platinum.