Mother Monster quickly deleted the accidental nip slip pic, but her sister Natali managed to score a screen grab of the wardrobe malfunction and couldn't resist re-posting it.
"Long live the nipple! Ladies and gentleman, my sister #screenshot #love," she captioned the photo, which Instagram has surprisingly not yet deleted.
Right after it happened, Gaga adorably tweeted, "where is the face palm emoji when you need it," which we thought was the most perfect reaction ever - until Natali posted this photo and caption combo. She is probably the only one who could have pulled this off and she totally nailed it.
No matter how famous Gaga is or how grown up the Germanotta sisters are, they're still sisters and sometimes that means teasing each other, even if it's in front of thousands of people.
Your move, Gaga!