The singer popped by as a friend from camp on Fallon's popular "Ew!" segment.
With the host doing drag to play teen talk show host Sara, Spears popped by as one of her friends from summer camp, a crop top, mini-skirt wearing girl named Abby.
With Fallon barely understandable thanks to Sara's braces and California girl accent, we're shocked Britney didn't break during the segment as the two talked about poison ivy, Abby's obsession with horses and throwback photos Sara thought proved they're "practically twins." They didn't.
While discussing whether they'd return for one more year of camp, Abby said she thought they were too old to be campers, while Sara said they're still too young to be counselors. "It's like I'm not a girl," began Fallon, as Spears sang the line from her song, "not yet a woman" to applause.
The two then played a game called Fashion Freeze, where they showed off their model poses. As anyone who follows Britney on Instagram can attest, she knows how to put on a fashion show, so her movements were #flawless. Sara's, not so much.
The segment ended with Sara asking her BFF to reveal whether she thought a speed round of items were "Ew!" or not. While they agreed that sun dried tomatoes were double yuck, Abby shared she thought one unsuspecting actor was "so cute": Steve Carell.
Her reasoning: "He's like a really talented actor, have you ever seen Despicable Me 3?" Watch the video above -- and see more of Fallon's "Ew!" segments below.