Serial-dater Swift donned braces and pigtails to appear as nerdy Natalie alongside Jimmy Fallon in his hilarious "Ew!" segment on the Tonight Show on Wednesday, Aug. 13.
But while her train-track mouth gear and geeky glasses delighted the audience it was her insistence that she would never get back with an ex-boyfriend that drew the most laughs.
Swift joined the list of famous "Ew!" alums which includes Channing Tatum, Zac Efron, Michael Strahan and Lindsay Lohan with her rendition of 13-year-old Natalie Benson, who likes to eat apricots and has a band-aid collection.
Audience members went wild as Fallon — aka Sara — and Swift started dancing to Selana Gomez's "Come & Get it." But it was the “Red” singer's quick-fire "Ew!" speed round that really got the laughs.
After relegating rice pudding, yield signs, cellphone airplane modes and breaking up to the "Ew!" pile, Swift made her thoughts on getting back together with a former flame quite plain.
"Ew!" she said. "Never?" asked Fallon. "Never, ever, ever, ever, ever!" replied Swift to peals of laughter.
Click on the link above to watch the entire segment!