Songfacts®:

• TK-421 is a stormtrooper in the original Star Wars movie tasked with guarding the Millennium Falcon. He isn't very good at his job - he's killed and Luke Skywalker puts on his uniform as a disguise to rescue Princess Leia.
  
  It was another movie, though, that inspired the title of this song. In the 1997 film Boogie Nights, Don Cheadle's character, Buck Swope, is working at a stereo shop trying to talk a customer into getting the TK421 modification - a little Easter egg in the film courtesy of its director, Paul Thomas Anderson. Lenny Kravitz loves the movie and used this scene as impetus for the song.
  
  "He starts to tell him all of these things, like it gives it four or five more quads per channel," Kravitz explained in a video. "He doesn't really know what he's talking about - he's just bulls--tting the guy to spend this money to do the modification. I use that as a metaphor because the TK421 is this thing that makes it better, that gives it more power."
• Kravitz says the song is "about positivity, positive energy, positive spirit," common themes in his music.
• "TK421" was released as the first single from Kravitz' 12th album, Blue Electric Light. He chose it as the debut single at the behest of Bono and The Edge of U2, who got a preview of the album and told him it was the one.
• Kravitz is naked for much of the music video, which was directed by Tanu Muino and shot at his house in Paris. He was 59 at the time - the diet and exercise routine he followed was clearly working.
  
  Muino is Ukrainian, a heritage shared by Kravitz, whose great-grandfather was born in Kyiv.
  
  "I hired this young Ukrainian woman director, Tanu," Kravitz told The Guardian. "She had this idea: we're going to come to your house, you're going to wake up and open the curtains, get ready for your day … I thought that sounds like the most boring thing ever. Then, when she gets there, she says: 'So you sleep in the nude, yeah?"
  
  So why does Kravitz think the video worked? "We're having fun, I'm singing into a toothbrush, dancing around the bathroom," he said. "It wasn't the energy of: 'Ooh, let's be sexy.'"