Britney Spears Concert on 'GMA': Singer Wows Thousands of Fans at San Francisco Concert

SAN FRANCISCO, March 27, 2011 — -- Britney Spears made 5,000 fans very happy today, performing a concert for "Good Morning America" at the Bill Graham Civic Auditorium in San Francisco.

Singing three songs from her new album "Femme Fatale," Spears danced on stage, wowing the packed auditorium.

The new album -- her seventh -- comes out on Tuesday.

Watch "Good Morning America" Tuesday to see the full concert and hear Spears' special announcement.

Spears, 29, greeted the crowd in a silver sequined body-suit, and sang "Hold It Against Me."

Her adoring fans, some of whom had been camped out all night, held signs and screamed for the pop star.

"I thought it was amazing. She was really great," said Sarah Ammann, a fan from San Francisco.

"She's the ultimate performer. She's definitely back," added Alicia Kennon of Brentwood, Calif.

Spears changed costumes and surprised the crowd by coming out of a speaker, dancing and singing "Big Fat Bass."

Wearing a black leotard and a black officer hat, she climbed on speakers that were set up on the stage, to cheers from the concertgoers.

For her last song, Spears sang "Till The World Ends," wearing a black leotard spotted with flashing red lights and fishnet tights.

CLICK HERE for photos from the concert.