Beyonce has let it slip that she will be singing "At Last," the standard Etta James made famous, for Barack and Michelle Obama's first Inauguration night spin around the dance floor.

"I am so honored that I will be performing for President Obama and the First Lady," Beyonce said in a statement, Perez Hilton reported. "To sing 'At Last 'while they have their first dance is a dream come true."

 Beyonce, who portrayed Etta James recently in Cadillac Records might have let that secret slip when she wasn't supposed to. A Presidential Inaugural Committee spokeswoman said earlier, "It is our hope that we can keep the song secret until the moment."

Also appearing at the Neighborhood Ball for the Inauguration are Beyonce's husband Jay-Z,  Alicia Keyes, Faith Hill, Mariah Carey, Maroon 5, Mary J. Blige, Shakira, Stevie Wonder, Sting, and will.i.am.

On her role in the Inauguration festivities Beyonce said, "I could not be more honored and excited that they have asked me to be part of this moment in history."