White wrote this for the 2009 electric guitar documentary It Might Get Loud. The White Stripes/Raconteurs guitarist penned and recorded the song in just ten minutes, with the film crew witnessing the song's entire genesis and completion.

This was Jack White's first ever solo single.

This might be the best modern song to have ever been written just to win an argument. Director Davis Guggenheim (who also directed An Inconvenient Truth) disagreed with White when White made the statement that most songs nowadays are over-prepared and over-produced. White improvised this on the spot just to prove his point.
By the way, deliberately under-producing songs is also one of the hallmarks of the punk rock movement. Garage rock, which will always be the close cousin of punk, shares this ideology. The argument goes that polishing and perfecting music, such as is done with progressive rock, may make it technically better, but at the price of sacrificing the passion and soul out of music.
For another feat of speed-song-writing, see Leiber & Stoller's "Santa Claus Is Back in Town," written for Elvis Presley in just fifteen minutes while his manager, "Colonel" Tom Parker, glowered at them for taking too long.