Joining forces on McBride's 2003 anthem, "This One's for the Girls," the trio got everyone on their feet early, while stars like Jana Kramer and Kelsea Ballerini sang along in the audience.
Luke Bryan scooped up the night's top award for Artist of the Year and Chris Stapleton took home honors for Album of the Year. Meanwhile, Brooks & Dunn reunited outside of their Las Vegas show to accept the Nash Icon award and perform their hit "Red Dirt Road."
Kevork Djansezian / Getty; Lester Cohen / Getty
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Other highlights from the show include:
Bryan jamming so hard with his band on "Huntin' Fishin' and Lovin' Every Day" that he declared, "It's hard to do a speech after you perform!"
Carrie Underwood showing off her moves in true golden-gladiator-goddess style during her performance of "Church Bells."
Florida Georgia Line toning down the testosterone for the TV debut of their brand new song "H.O.L.Y." – and the adorable, love-struck way their wives looked on.
Ronnie Dunn's speech after he and Kix Brooks won the Nash Icon award. "So here's how it goes," Dunn told the crowd. "I wake up in a parking lot tomorrow in a brown, whiskey haze at Caesar's Palace in Las Vegas with this Icon award sitting next to me and I go, 'You ain't no icon. You ain't no Johnny Cash. You ain't no Merle Haggard. You ain't no George Jones. You got a lot long way to go skinny boy with a record deal.' I'm proud of this, thank you!"
Toby Keith's tribute performance to the late Merle Haggard. Playing with Haggard's band the Strangers, as well as Haggard's youngest son Ben, Keith sang a montage of hits including, "Mama Tried," "I Think I'll Just Stay Here and Drink" and "Fightin' Side of Me."
Here's the full list of this year's winners:
American Country Countdown Awards 2016 Winners:
Artist of the Year–Luke Bryan
Male Vocalist of the Year–Luke Bryan
Female Vocalist of the Year–Carrie Underwood
Group/Duo of the Year–Florida Georgia Line
Song of the Year–"Die a Happy Man" by Thomas Rhett
Breakthrough Male of the Year–Sam Hunt
Breakthrough Female of the Year–Kelsea Ballerini
Album of the Year–Traveller by Chris Stapleton
Nash Icon Award– Brooks & Dunn