Underwood, who took home the award for "Video of the Year" for her song "Good Girl," dazzled in a Randi Rahm cocktail dress embellished with mini silver paillettes and $21,000 worth of Tiffany & Co. jewelry.
Lambert, who worked the carpet with her Pistol Annies girls, chose a strapless Georges Hobeika Signature Collection dress, Giuseppe Zanotti heels, earrings by J/Hadley and bangles by Kara Ackerman.
The host of the evening Kristen Bell wore a gold embroidered Reem Acra gown from the designer's spring/summer 2012 collection and Graziela earrings. (She later changed into a Collette Dinnigan dress during the show.)
Also among the stars without country record deals: Hayden Panettiere, who sported a swingy cream skirt by Praven paired with an embellished Giorgio Armani bodice and black Christian Louboutin heels. "I wish I was in cowboy boots!" the actress exclaimed to Us Weekly on the red carpet.