Beck was a surprise guest on The Late Show with James Corden, during Corden's second week as the new host of the show.
The show was set up as a bit of a gimmick, in which James goes out in to the streets, knocks on doors until he finds someone willing to let him film that night's show in their house. For numerous reasons, I doubt the show was actually as spontaneous as all that; however, it was indeed filmed in a man named Tommy's house, and Beck showed up (he wasn't announced as a guest until the evening it aired). Corden interviewed Beck briefly, before Corden, Beck, Tommy, Jeff Goldblum and Reggie Watts all played a game of hide and seek. (Beck hilariously hid under the rug.)
Beck then performed "Country Down" in Tommy's dining room. His band was Joey on drums, Gus on bass, and an as yet to me unidentified pedal steel guitarist.
The show aired on the evening of April 2, however some stuff came out which makes me believe it was actually recorded the week earlier on March 26. (I do not know why.)