Britney Spears' "Circus" Comes to Town

Britney Spears celebrated her birthday with a pair of performances on "GMA."

PHOTOS: Britney Spears' 'Circus' Comes to Town

Britney Spears
Britney Spears
Britney Spears
Britney Spears
Britney Spears
Britney Spears
Britney Spears
Britney Spears
Britney Spears
Britney Spears
Britney Spears
Britney Spears
Britney Spears
Showing off toned abs in a midriff-baring top, curve-hugging black leather pants and then hot pants, it was clear the singer has spent time at the gym and the dance studio getting in shape before the concert tour. (Jessica DiPietro/ABC)
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