Ask Carrie Underwood to describe her personality and you might end up in tears!

"I'm a big, fat onion," the singer tells Nashville's Tennessean newspaper. "I was talking with someone, and they were telling me about a conversation they had with someone I dated. The guy I dated said, 'People don't know her.' I never really thought about that until this person told me about the conversation. I've had people say, 'Hey, there's really a personality in there. Don't be afraid to be funny in front of people.' I'm getting better with that, but when you open that book and let people in, there's something scary about that. I guess I'm used to keeping people at a distance."

That came in handy, however, when the future superstar was a contestant standing before the judges on 'American Idol.'

"Oh, I never said anything on there," Carrie confesses. "Whenever judges would critique me, I'd keep my mouth shut. When I watch the show now and see someone talking back, I think, 'There you go, you're going home.' I learned to keep the book shut when I was on 'Idol' because everything you do is so scrutinized. It kind of scares you into your shell."

But beneath that protective outer shell bubbles a quirky sense of humor Carrie doesn't often display in public.

While at a recent Nashville Predators vs. Ottawa Senators game she attended with friends, Carrie suddenly realized she was on the arena's cameras -- and promptly ducked for cover. Although she did it to be zany, her friends cringed, figuring she'd just given the tabloids a great shot that would be misconstrued!

"I'd been to Preds games before, and they tend to put me on the JumboTron five minutes in," she says. "And then everyone knows where I am, which means I get to meet people but not to watch the game. This was a Predators game, but my boyfriend [Ottawa Senators' center Mike Fisher] was on the opposing team. I saw the camera, and ... I'm stupid, so I ducked. I have no excuse. One of my friends told me, Anything you could have done would have been better than ducking. But ... I thought it was funny. I'd duck again."

Expect the more "open book" version of Carrie when she co-hosts the CMA Awards with Brad Paisley live on ABC, Wednesday, Nov. 11 at 8 p.m. (ET).