Lambert offered collabs with Leon Bridges, Elle King and Avril Lavigne on night two.
Vince Gill made a surprise appearance, while several artists made their CMA Fest Nissan Stadium debut performances.
“There’s nothing else like it in the world,” says this year’s opening-night headliner, Luke Combs.
'CMA Fest' will air Wednesday, July 19 on ABC.
The documentary will feature artists including Keith Urban, Wynonna Judd, Reba McEntire and Frankie Staton.
Dierks Bentley, Mickey Guyton, Hailey Whitters, Ingrid Andress, Old Dominion & more will also join them June 8-11.
Allen was slated to perform Sunday, June 11, during CMA Fest in Nashville.
