Who’s the mystery artist who’ll close Big Machine 20?

An “award-winning superstar group from the label’s roster” will close out Big Machine 20, according to a news release from the company.

Riley Green, Sheryl Crow, Carly Pearce and Brett Young are already on board for the free Friday concert that starts at 7 p.m. CT on Nashville’s Lower Broadway. 

The Band Perry, RaeLynn, Danielle Peck, Danielle Bradbery and Jack Ingram will also play the show that celebrates two decades of Big Machine, as well as Aaron Lewis, Preston Cooper and The Jack Wharff Band.

It seems Rascal Flatts is a likely contender as the mystery act, having been on the label since 2010, though Lady A and Midland are Big Machine artists, as well. 

Big Machine 20 kicks off the Borchetta Bourbon Music City Grand Prix Friday in Nashville.