The six-time Grammy winner revealed to Matt Lauer:
"I had three or four pairs of Spanx on that night but I loved it. I actually had another dress made and I ended up passed out in it. It had a corset and I was like, 'I can't wear that,' so I ended up wearing this instead."
And that's why we love you, gurl! Keepin' it real!
[Image via WENN.]