Nashville's honky tonks see a variety of people, from international tourists to struggling musicians. And sometimes, musical geniuses will share a stage ... as was the case with Keith Urban and Steven Tyler over the weekend.

On Friday (Sept. 6), Urban kicked off an unofficial Honky Tonk Tour, completing it in less than one hour to promote his album, 'Fuse,' which will hit store shelves Tuesday (Sept. 10). The rendezvous began at Cumberland Park, where the superstar started the evening with 'Long Hot Summer' and continued with country rocker Eric Church, who joined him onstage for 'Raise ’Em Up.'

Then, Urban traveled to three well-known honky tonks in Music City, including Legends Corner, Tootsie’s Orchid Lounge and the Stage, playing four different songs in each of the venues and lighting up lower Broadway with his contagious stage presence and screaming fans.

When he hit up Tootsie's, the fans in attendance got a major surprise when, after playing a spectacular riff to ZZ Top’s 'La Grange,' Urban said: "I'm going to attempt an experiment right now. I'm going to predict if we play this riff long enough, we might find a singer in the crowd who knows how to sing this song."

He grinned, adding cunningly, "If you happen to be a bit of a bad a-- blues legend singer, this might be your cue."

It was then that the one and only Steven Tyler emerged and started singing 'Walk This Way,' much to the delight of the jam-packed audience. It isn't every day that Urban graces the honky tonks -- much less with one of the world's most beloved rockers.

In addition to performing, the 'Little Bit of Everything' singer gave out autographs and hugs to the crowds that showed up to catch a glimpse of the Aussie superstar star.

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