Blake Lively stopped by the show this morning to talk about her upcoming film, "Green Lantern," in which she plays Carol Ferris, the childhood sweetheart of Hal Jordan, who is selected to become a Green Lantern.
Every Green Lantern has to take an oath. Matt dared Blake to recite it from memory -- and she agreed only if Matt joined her.
Watch the following video to see if Matt and Blake were able to. And test yourself! The full oath is listed below the video.
The Green Lantern oath:
"In brightest day, in blackest night, no evil shall escape my sight. Let those who worship evil's might, beware my power -- Green Lantern's light!"