Sturgill Simpson is becoming a common name on late-night TV. The singer, who recently performed on both the 'Late Show With David Letterman' and Conan O'Brien's show, 'Conan,' visited the set of the 'Tonight Show Starring Jimmy Fallon' earlier this week.

Simpson performed his single 'Turtles All the Way Down,' from his 'Metamodern Sounds in Country Music' album, which was released earlier this year. The song, he says, is a slightly humorous explanation of one form of spirituality.

"The turtle myth is kind of a comedic expression in metaphysics now. It represents a much grander idea of what is known as the Unmoved Mover, or this one central divine source of all complex consciousness in the universe," Simpson tells Rolling Stone Country. "And according to the theory -- and I say theory because I don't ever want to say I agree with it -- but it is still a beautiful idea that everything is being emitted from one point and that we're all this universal shared consciousness."

While Simpson's latest appearance has earned him even more fans, the singer-songwriter recently discovered one of the downsides of being in the public eye, when he was criticized for using a curse word in his performance of his song 'Living the Dream' on 'Conan.'

“Been some folks coming to my page to chastise (judge) me for taking the Lord’s name in vain on Conan so figured I should address it,” he wrote on his Facebook page. “Ironically, the song is actually a metaphor comparing the soothing yet completely addictive and damaging effects of hard narcotic opiates to the negative sociological impact of organized religion and blind faith when forced upon society and used as a political tool by self-righteous, thinly-veiled bigots to control and manipulate the masses and enhance the suffering of impoverished, lower class citizens.”

Simpson will spend much of the fall on the road, including shows in Louisiana, Alabama and Florida. See a list of all of his upcoming shows here.