The country music celebration kicked off with a special tribute to the late Loretta Lynn, who died Oct. 4 at age 90.
Luke Bryan and Peyton Manning host the awards show in Nashville.
"Unfortunately, I'm under the weather," Allen said.
Reba McEntire, Carrie Underwood and Miranda Lambert will team up to honor the late artist.
Previously announced performers include TOMORROW X TOGETHER, ENHYPEN and IVE.
The victors for musical event of the year and music video of the year were revealed Wednesday morning.
Luke Combs, Brothers Osborne, Reba McEntire, Carrie Underwood, Morgan Wallen and more are set to hit the stage.
The BMI country song of the year honor went to the Luke Combs hit "Forever After All."
Will Lainey Wilson turn her six nominations into trophy wins? Will Morgan Wallen secure his first male vocalist and/or entertainer of the year wins?
"It’s really significant for your career, getting the nominations, but it’s because something significant has [already] happened in your career," Clint Black says.
