The 43-year-old was performing at the Unipol Arena in Bologna on Thursday night when the incident happened.
The "nip-slip" wasn't her only wardrobe malfunction during her performance this week as even her Spanx could be seen through her form-fitting Zahair Murad catsuit, reported Radar Online.
Last Oscars as well Lopez allegedly suffered a slip during the awards show, but the actress denies this claim.