And even she admits her performance wasn't perfect.
"Some of my notes were pitchy to me," she said Monday on Dan Patrick's radio show, according to USA Today.
Still, she said, "It was so exhilarating. The whole thing. it was so big. That's a once-in-a-lifetime thing."
"It's such a huge venue, your nerves take a hold of you," said Fergie. "I completely understand. She's one of the best singers of our time. Nobody can take that away from you. ... But you get nervous at these things. We're human."