This diary from an attendee seems to think she might have attended the big Tennessee music festival. There certainly seem to be a lot of celebs there so its entirely possible.
Spotted: one of the tiny Olsen twins making her way into the artist area backstage.
Bruce Springsteen, Of Montreal, Drew Barrymore and Justin Long watching MGMT from side stage.
Natalie Portman or her doppelganger watching MGMT from side stage.
I like MGMT’s album but the few times I’ve seen clips of them live, I’ve been VERY turned off by their performance.