Jennifer Lopez Is NOT Pregnant

Jennifer Lopez is not pregnant ... not even a little bit.

J Lo's longtime friend and manager, Benny Medina, tells TMZ, the stories floating around that Jennifer is pregnant are "100% not true."

Medina doubled down, sending us the pic (above), snapped late last night ... after her Vegas show. Medina said, "Does this look like pregnant?"

Two other sources in a position to know -- especially one -- confirm, she's not pregnant.