Britney Spears stopped by Jimmy Fallon where Sara (Jimmy Fallon) and her sleepaway camp BFF Abby (Britney Spears) compared Throwback Thursday Instagram photos.
They also played a made-up game called Fashion Freeze.
There's even a reference back to Britney's song "I'm not a girl... not yet a woman."
Ooooooooh, you have to see for yourself!