Where have the Flight of Conchords been hiding? Stephen Colbert demanded answers from Bret McKenzie and Jemaine Clement when they stopped by The Late Show on Monday night. The duo are promoting their upcoming HBO special, Flight of the Conchords: Live at the London Apollo, which will air next month. And to celebrate, they gave fans a peek with a performance of "Father & Son," a sweet and surprising song about, well, a father and a son and a guy named Trevor.

In addition to the performance, The Late Show also released the full, unedited interview the two did with Colbert, which includes nuggets like why fame is like a horse. As Clement explains, "That old horse, fame. That’s a wild beast, isn’t it? It can take you on a nice ride, it can buck you off." Colbert suggests, however, that “you could also braid its tail!” Sure!

Check out the interview below, followed by the performance: