Blake Lively's knowledge of 'Harry Potter,' four letter words will impress you

Blake Lively is a Know It All.

The actress, who was baby bumpin' in blue on The Tonight Show Monday, schooled Jimmy Fallon in their meeting of the minds.

The Shallows star joined the late night host for the game where each player takes turns picking a category, and the opponents go back and forth giving responses that fit in the specified category.

Making something up is always an option if one runs out of answers, just note an opponent can definitely call one's bluff.

Warning: This clip gets NSFW when we get to the four letter words category.

J.K. Rowling might be excited to know that the first category Lively picked was Harry Potter characters. And, obviously this HP aficionado nailed it. Remember her Deathly Hallows mani?

For the next category, Fallon said hola to Spanish words, which both players struggled with. It was no bueno.

For the final round, Tonight Show announcer Steve Higgins chose the category four letter words. Ryan Reynolds' wifey dominated again and was crowned the champ. Good thing since she was playing for two.