We would suspect that Jennifer Lopez is nursing a bruise on her back after falling on stage during her performance at the American Music Awards last night.

Fortunately, that famous booty of hers helped cushion the fall somewhat.

After strutting on the stage, converted into a boxing ring, in a robe and gloves to sing "Louboutins" from her new album, Lopez gyrated with male dancers.

It was all going according to plan until J. Lo climbed onto a human pyramid of half-naked performers and jumped down, slipping and falling on stage. Ow.

Check out (and laugh at) J. Lo taking a spill below ...