The 23-year-old actress joined fiancé Evan Peters and their fellow costars Sarah Paulson, Gabourey Sidibe and Angela Bassett, among others, to represent the show's third season, Coven, at the event in Hollywood.
Peters told People magazine that the opportunity to work alongside Roberts on Coven was "really amazing."
"You're at set and you're in a city that you don't really know that well," Peters said of the season's New Orleans location. "It's nice to have your best friend there to go to dinner with and check the city."
"On set if you're having a bad day or whatever, you can go to somebody and talk to her and she's right there," the actor continued. "You don't have to wait until you're done working, so it was nice."
The big news of the evening was actor Michael Chiklis' announcement that he will join the American Horror Story cast for its fourth season, Freak Show. The announcement also confirmed that Roberts and Peters will make a return for the fourth season.
"We're going to freak you out and scare you! Every person on this stage is coming back!" Chiklis exclaimed. Roberts and Peters, Kathy Bates, Angela Bassett, Sarah Paulson, Gabourey Sidibe, Francis Conroy, Jamie Brewer and Denis O'Hare were all on stage at the time of the announcement.