"It's the hardest thing I've ever done," Paulson told ET's Kevin Frazier on the red carpet outside Elle's Women In Hollywood celebration, where her AHS co-star Jessica Lange was being honored for her work.
"It's the most exhausting thing I've ever done. And for all the other actors, it's one of the hardest things they've ever had to do. Because when I'm shooting, I've got one head, and they have to imagine where the other head is going to be."
"I don't know what American Horror Story would be without her," Paulson, 39, said. "I hope she stays. I wish I could say I have some insight, but I've got everything I could possibly cross -- I've got both heads crossed."