While the Easy A star is the undisputed queen of the Tonight Show Lip Sync Battle, she didn't fare quite as well when she slipped on a pair of noise-canceling headphones and tried to guess Fallon's song clues.
He kicked off the game with Bruce Springsteen's "Born in the U.S.A." but Stone, 28, struggled.
"Whatever you're doing looks inappropriate," she said with a laugh.
So Fallon tried reciting the first two lines of the song again.
"Just kick it in the ground," Stone suggested. "Pork?"
"Born! Born!" the Saturday Night Live alum pantomimed as he lifted his legs in the air.
"Birth! Boy?" Stone suggested before she finally got it right.
Next it was her turn, and she sang Britney Spears' "…Baby One More Time."
"Eat?" Fallon responded. "What you're saying is inappropriate."
Stone sang the line again, showing a glimpse of the vocal range she displays in her buzzed-about new musical film, La La Land, with frequent costar Ryan Gosling. (They previously paired up in 2011's Crazy Stupid Love and 2013's Gangster Squad.)
Fallon then did an impression of Elvis Presley singing "Blue Christmas" that totally threw his guest.
Watch the video above to see Stone give the next clue.
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