The “Factory Girl” actress was spotted making her rounds with a girlfriend, sporting a weather-appropriate sleeveless black shirt with matching shorts, a black and grey hat and an interesting looking pair of leather shoes.
Miss Miller was in good company, as it has been estimated that there were over 150,000 sweaty music and art fans in attendance over the weekend.
As could be expected, Sienna was all over the place, talking to fellow festival-goers on the lawn, and checking out concerts by Prince and Roger Waters.
And it sounds like the Roger Waters gig was the end-all of the festival, with a giant inflatable pig floating over the crowd.








Brody Jenner
Spencer Pratt
Justin Bobby
Jason Wahler
Stephen Colletti