During her visit, the 27 year old star joined Fallon for a sketch about two teen girls called "Ew."
"I'm Sara," Fallon says at the beginning of the sketch, "and if you're wondering, that's S-A-R-A. No H, because H's are ew!"
You check out Fallon's girl voice and Lohan's scrumping moves in the clip below.
Celebrity Couples of 2014 [PHOTOS]