"This is Armani Privé. I'm actually here for Red Carpet Green Dress," she said. "Suzy Amis Cameron started [RCGD] to bring awareness to living a sustainable life. So this dress is sustainable, because it's vintage."
"And I'm kind of in shock that I'm here," she added. "It's surreal. It's so fun, and it's so nice to, you know, I go to events a lot, but it's nice to come to something like this, and have a reason that you feel good about, and something behind it."
For more on ET's interview with Roberts, watch the video below.