As he's repeatedly made clear over the years, Robert Plant does what he wants, when he wants. And lately, that means showing up in some unexpected places.

On July 15, Plant stunned the audience at BJ's, a small New Orleans club, when he appeared unannounced for a two-hour set with the night's expected headliner, Guitar Lightnin' Lee. Describing it as "amazing," one YouTube user (whose clip you can watch above) called the show a "blues jam that included 12-bar and shuffle versions of ‘Black Dog,’ ‘Since I’ve Been Loving You’ and more."

Plant, who's currently touring the region, has a history of making surprise appearances in New Orleans. He also recently turned up unexpectedly in Memphis, where he sat in on a recording session for the next North Mississippi Allstars album, contributing harmonica to a track.

"We let him use Al Green's mic," said Boo Mitchell, who owns Royal Studios, the Memphis institution where the sessions took place. "He dug the sound and the fact that we haven't changed anything. He had a fabulous time ... He should play harmonica more than he does. He is a badass harmonica player."