Wilco frontman Jeff Tweedy performed this week at the book release party for Dan Sinker's new book, and surprised fans with an unplugged cover of the Black Eyed Peas' "I Gotta Feeling".  The event was held in Chicago at the Hideout.  Watch some quality footage of the performance below.  Wilco's new album titled "The Whole Love" is set to hit stores September 27th.  It will be the first album released on the band's own dBpm label.