Yes, she’s had a couple of songs on country radio, and yes, she’s opening for Kenny Chesney these days. But now we know Kacey Musgraves has arrived: Her voice is on a national commercial for Oreo cookies. Kacey does a version of the Oreo “Wonderfilled†songin which she wonders what would’ve happened had she offered an Oreo to a cute guy she had a crush on in the past. As she’s singing, stick-figure Oreos act out the lyrics. It’s super-sweet—like, say, Oreos . . . and Kacey.