A few weeks ago, the Black Keys played a secret club gig in their adopted hometown of Nashville, during which they filmed a video for 'Little Black Submarines.' While the video is not yet available, the single is ready for release.

'Little Black Submarines' begins with Dan Auerbach's fingerpicked acoustic guitar. There are touches of 'Can't Find My Way Home' by Blind Faith in the melody as he sings of his broken heart. Percussion and organ enter the picture in the second verse.

Halfway through the song, they dispense with the polite acoustics and go into their best Led Zeppelin mode, with Patrick Carney flailing away on the drums and Auerbach throwing out quick guitar fills between his vocals and power chords. It all makes for an enjoyable and easily digestible listen in the way that has made the Black Keys famous.

Still, it's hard to figure out what kind of imagery Auerbach is going for with the title. What does a little black submarine have to do with trying to win back his girl? Is he serving in the Navy? Besides, submarines are usually big and gray (although yellow and pink submarines have been spotted in pop culture), not little and black.

Listen to the Black Keys, 'Little Black Submarines'