The actress-singer talked about her injury and explained why she fell during a segment on Thursday's Ellen Degeneres Show, reports People.
"I have a bruised bone," she told host DeGeneres.
Lopez added: "What happened was one of the dancers' backs was slippery from sweat and lights and everything. We never bargained for that because they always had T-shirts on in rehearsal.
"So they were barebacked, didn't have shirts on for the performance and when I stepped on their backs, my feet got wet. So when I landed, it just slipped from under me."
The 40-year-old recently joked that her on-stage stumble was a planned part of her choreographed routine.