Fans lined up at midnight, some camped out at Civic Center Plaza. Lots of people waited to see Britney in the flesh.
"The helicopters and I are arriving at the same time. It's so exciting. San Francisco is on fire," said Britney fan Sister Roma.
Once the doors opened, it took 90 minutes to fill the Bill Graham Civic Auditorium. Good Morning America's Robin Roberts and Sam Champion were right behind the fans as Britney was getting ready to debut her new album "Femme Fatale."
So what is it that attracts some many people to Britney Spears?
"She is what she is and she's been through the ups and downs and always comes out on the upside of it," said Roberts.
"I've been humming 'Holding It Against Me' all day. In the car everyone's like, 'Sam, stop!'" said GMA's Sam Champion.
ABC7 was told we could only show Britney singing one song and are not allowed to give it all away. If you want to watch the entire concert you have to watch Good Morning America on Tuesday.
"Oh, Britney Spears is amazing. I've loved her forever, since she came out with her first single," said Britney fan Stephanie Liu.
Some thought the pop star was a little rusty.
"She's definitely not dancing as much as we would want her to be dancing, so hopefully this is her warm-up and she'll get better," said Britney fan Suzanne Kling.
You can judge for yourself on Good Morning America on Tuesday. Good Morning America airs from 7 a.m. to 9 a.m. on ABC Channel 7.
