Beyoncé may have been able to fight back the tears onstage while singing "At Last" for Michelle and Barack Obama's first dance at the Neighborhood Ball. But afterwards, when she described how amazing it was to be a part of this historic occasion, she couldn't contain her emotions for very long.

"I can't even describe to you how I felt," she told "Good Morning America" correspondent Robin Roberts after her performance. "I'm actually right now fighting back tears because it's just so emotional. I'm just so proud of my country. There are just certain people in the world that God touches, and this man was born for this. And he was born to lead us, and I just feel so inspired and so proud."

She also explained what she was thinking about as she sang the Etta James classic for the first couple. "I was thinking [about] all of the sacrifices Obama and his wife and his children have made, and at last he's here," she said, her voice wavering. "I'm sorry, I'm so embarrassed. I'm just so lucky to be a part of this history. It's probably the most important day of my life, and I'm so grateful."

Beyoncé told Roberts that Obama's victory has changed her. "He makes me want to be smarter; he makes me want to bee more involved," she said. "Honestly, of course, I've voted before, but I've never really watched the ceremonies. This is my first time being a part of it, and I'm here, and I'm singing! ... I'm so overwhelmed, you know. I have chills!"

Watch "Be the Change: Live From the Inaugural" online now, and come back Thursday for the full performances from Kanye West, Kid Rock and Fall Out Boy. Stick with us for wall-to-wall coverage of the inauguration and of the scenes in Washington, D.C., New Orleans and Kenya.