Gaga goes cuckoo! The singing sensation lost it at a baseball game, stripping down to her bra and glittering panties and cursing out fans and photographers!

Lady Gaga showed up at Citifield, home of the New York Mets, dressed in a leather jacket and fishnet stockings. When she got to her seat, she had a complete meltdown that shocked everyone.

So what sparked Gaga's tantrum?

Her front row seat was right behind home plate, giving photographers covering the game a clear shot of her. That's when she flipped out.

She stripped down to a bra and bikini bottom, and then, as the crowd of 32,000 started booing, she made obscene gestures.

Stadium officials moved her out of sight, to a private box owned by comedian Jerry Seinfeld.

Gaga's baseball flip-out came just one day after she showed up at her sister's high school graduation in an outrageous outfit, including a beekeeper's hat and see-through pants.