The 30-year-old "High Horse" singer wowed on the red carpet in Valentino couture, which featured tulle and a pink sash, with Neil Lane jewelry.
"It's really actually so comfortable. I feel like that is a rarity," she told ET's Sophie Schillaci and Apple Music's Zane Lowe. "Sometimes you're like, 'I can't breathe and it's fine, my ribs are cracking in half.' But this one's fine!"
The stunning look reminded Musgraves of a fan, which has a very special meaning to her.
"I guess a little secret is that it kinda reminded me of a fan, which is kind of a nod to the cover of my album," she revealed. "So that's one reason why I really liked it."
It's a big night for Musgraves. The country star is nominated for Album of the Year, Best Country Solo Performance, Best Country Song and Best Country Album. She is also one of the artists who will take the stage to perform this evening. Other performers include Lady Gaga, Dua Lipa, Travis Scott, Cardi B and Diana Ross.