We know his music ... but yesterday in L.A., we finally saw Avicii's face -- as the DJ behind the smash hit "Wake Me Up" left a Hollywood nightclub.
The 24-year-old Swedish DJ was leaving Hooray Henry's ... when we asked how it felt for a guy from an electronic music background to become such a huge force in the rock world.
For the record, Avicii doesn't sing on "Wake Me Up" -- the voice you hear is singer Aloe Blacc. The song also features some acoustic guitar from Incubus rocker Mike Einziger.
Now play the video ... and good luck getting the song out of your head today.