Little Big Town are celebrating the birthday of singer Karen Fairchild today in between shows on Luke Bryan’s Kill the Lights Tour, a trek that has seen both superstar acts fill their respective setlists with plenty of familiar hits. With their gift for shimmering harmonies, throughout their 15-plus years together the quartet has covered a wide range of artists in concert, from the country-infused rock of the Eagles and Fleetwood Mac to Bruce Springsteen and Dolly Parton.

The foursome has been joining Bryan onstage for an extended medley that includes a slithering, sensual take on Marvin Gaye’s “Let Get It On.” But it’s the group’s sweltering, soulful rendition of Grammy winner Alicia Key’s worldwide hit, “Fallin'” that stands out as a highlight of their current set.

Although Wanderlust, the group’s collaborative, experimental (and decidedly non-country) side project with songwriter-producer Pharrell Williams was released to minimal fanfare earlier this year, they are reportedly working on a new country record to follow 2014’s gold-certified Pain Killer.

Luke Bryan’s Kill the Lights Tour, with Little Big Town and Dustin Lynch, continues Friday, September 30th, with a two-night stint in Salt Lake City. See LBT’s tour dates here.