Keith Urban wowed the the late-night crowd with an impromptu banjo cover that might surprise you. This week on The Tonight Show Starring Jimmy Fallon, Urban stopped by to promote his new album, High. Right before leaving the show, the country star pulled out his ganjo (6-string banjo) to show everyone just how talented he is. Check out the surprise performance below. https://www.instagram.com/reel/DAUwaHEOnMM/ The Aussie covered “Espresso” by Sabrina Carpenter, which seemed to fit his falsetto vocal perfectly, and he added his signature banjo sound to the performance. Lots of fans in the comme…