Update, August 13: The Night Sweats’ debut album is now streaming on NPR’s First Listen.

We at 5280 have been tracking the rise of Nathaniel Rateliff for years. We even named him Denver’s best musical act in our 2014 Top of the Town issue.

Our admiration for him stemmed from his beautiful and pensive songwriting and a mellow and folky style that he’s referred to as “desperate but hopeful.” But Rateliff’s latest project might have even his most seasoned fans doing a double take. With The Night Sweats, his seven-piece R&B combo, Rateliff is bursting into entirely new territory.

Last week, the band made its national TV debut by tearing up the stage on The Tonight Show, a performance packed so full of old-school energy that host Jimmy Fallon could barely contain himself. (He rarely does, but still.)

Rateliff fronted the combo with his signature Joe Cocker-esque growl, and he threw in some James Brown-style crazy-legs moves to complement his band’s exuberant horn section and airtight percussionists, to the delight of Fallon and his audience.

The Night Sweats will release their debut self-titled album on August 21 (pre-order here) and then will hit the road for an American and European tour that runs through Thanksgiving. Local fans can catch them multiple times in the next month in Paonia, Fort Collins, at Red Rocks, and the Telluride Blues & Brews Festival. Just make sure to bring your dancing shoes.

Follow 5280 editor-at-large Luc Hatlestad on Twitter at @LucHatlestad.