It was announced earlier this month that L.A. alt-rockers Grizfolk would make their debut on the Late Show With David Letterman on Feb. 18. What the band failed to warn people about was the fact that they planned to absolutely kill the performance. Last night, Grizfolk performed their popular song "Hymnals" from their debut EP, From The Spark -- you can watch the staggering gig in the video above.

During the Letterman set, they sound as if they're a supergroup made up of the Killers and Motion City Soundtrack, giving it their all and making themselves known to the world in a matter of just a few minutes. Dave was even floored and, in his usual style, told the band that he's going to keep their EP.

Grizfolk recently finished a tour opening for Bastille and now are hitting the road for their own run of headlining dates. Their tour will pass through Pot of Gold Festival in Tempe, Ariz., Hangout Festival in Gulf Shores, Ala., Boston Calling and BottleRock in Napa, California. You can get a full list of their scheduled tour dates at their website.