‘Jenny from the Block’ has a potty mouth.

The superstar singer-turned-singing competition reality judge accidentally dropped the F-bomb while critiquing contestant Jena Irene’s performance of Evanescence’s hit “Bring Me To Life.”

“Jena, you sound phenomenal,” Lopez said. “(Harry Connick Jr.’s) right, the minute we hear your voice it’s soothing, it’s like, ‘Oh, my god,’ and she’s gonna sing it great. The only thing I would say is I wanted you to be more messy. Do you know what I mean?”

She was talking about Irene’s hair, which became disheveled when she threw herself toward the crowd.

“I wish it would have been more messy,” Lopez said.

Fellow judges Connick and Keith Urban teased Lopez chanting, “Hair flip! Hair flip!.”

And then came Lopez’s little slip up.

Clearly embarrassed, the “I Luh Ya Papi” singer covered her mouth as Connick said, “That’s Jenny from the block!”

Lopez didn’t let her flub get to her and quickly returned her attention to Irene.

“Listen, that’s all I would say. Even watching (Caleb Johnson), you saw it he doesn’t care his hair is everywhere, it’s crazy,” she said. “That’s what you need to do when you sing a song like that because we were so with you and that’s what we needed you to do to take us even further. Great job, though! Amazing job!”

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