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Carrie Underwood is nervous she'll make a performance fumble at this Sunday's Super Bowl. Said the singer, 26, who will sing the National Anthem, "My biggest fear is the words.

"Of course you know the words," she continued to USA Today. "But if you're going to mess up, that'd be the time, right?"

Check out pics of Carrie and Mike and other stars who date athletesUnderwood -- who says she'll be rooting for the Saints -- also joked about her fave new song: "Pants on the Ground," as performed by General Larry Platt on American Idol two weeks ago.

"As a songwriter I know we all aspire to write something that is catchy and has a message," she said. "And I think the youth of America can learn a lot from Pants on the Ground. And they can pull their pants up... because it causes all kinds of back problems. I've seen the studies."

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