Britney Spears on 'GMA': What Fans Are Saying

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The singer’s San Francisco performance airs on ABC the day her album, Femme Fatale, hits stores.

What did fans think of Britney Spears' Good Morning America concert in San Francisco?

"I thought it was amazing. She was really great," Sarah Ammann told ABC.

The 5,000 free tickets were snatched up in 14 minutes, but fans lined up at midnight on Sunday, when the concert was taped, in hopes of getting in.

"She's the ultimate performer. She's definitely back," said Alicia Kennon.

Spears sang three songs: "Hold It Against Me" (in a silver sequined bodysuit), "Big Fat Bass" (in a black leotard and black officer hat) and "Till the World Ends" (in a black leotard with flashing red tights and fishnet tights).

"I thought it was good, she looked really good and the crowd was into the last song," added concertgoer Nick Casey.

GMA anchor Robin Roberts, who emceed the concert with Sam Champion, called the show "phenomenal…the energy, the people, the dancing the music, Britney -- it was tremendous!"

Spears' seventh studio album, Femme Fatale, hits stores Tuesday.