One's a little bit country. The other's a lot rock 'n' roll.

Bo Bice (search), the long-haired 29-year-old from Helena, Ala., and Carrie Underwood (search), the 22-year-old farm girl from Checotah, Okla., give their final performances Tuesday night on "American Idol" (search) (8 p.m. EDT on FOX).

After that, it's up to America to decide who its "Idol" is.

Though Underwood has long been the odds-on favorite, Bice's a capella rendition last week of Badlands' "In a Dream" may have catapulted him into the front-runner position, as it floored the audience and the judges and was hailed by some as the performance of the season.

"You may have just put 34 musicians out of work," said notoriously nasty judge Simon Cowell (search).

Tuesday night, Bo and Carrie will be alone on stage when they perform three songs each: the "Idol" single, "Inside Heaven"; an original song and an established pop hit.

Although many predicted that these two would pair off together in the finals, Bo and Carrie say they never got too comfortable.

"A lot of people don't know this but I pack every night. Every Wednesday and every Tuesday night I pack just to make sure my bags are ready," Bice told FOX News.

In other words, shaggy-haired Bo knows how to stay humble, and his good-naturedness has helped him get this far. Even country crooner Underwood admits she is a little bit pro Bo.

"Of course I'll be nervous, but I'm OK with whatever happens. I wouldn't mind losing to Bo one bit. He's amazing. I mean if there's anybody to lose to, he's it. So you know, whatever happens — I'm good with it and that's what's supposed to happen," Underwood told FOX News.

Bice and Underwood may have different singing styles, but they both claim the same muse: their mothers.

Bice credits his mom, Nancy Downes — who raised him as a single mother after divorcing his dad when he was 3, sang with him in a touring family group and dared him to audition for "Idol" — for always supporting his career and even his "caveman" look.

"He's been considered a momma's boy," his mother told reporters — though there is no word what Bo thinks of that description. "There were nights when we were struggling with a mattress on the floor of a one-bedroom apartment, eating spaghetti every night.

"It was really tough," she said. "That's the reason I think we are so close."

Downes said she always had Bo's back — even when he decided to grow the long tresses which are now his trademark.

"He's had the hair from Day 1," she said. "Bo's hair used to be down to his waist. We just hated him because it was so beautiful."

As for Underwood, it was her mother, Carole — a retired elementary school teacher — who drove Carrie to her "Idol" audition 500 miles away in St. Louis.

Carrie, whose family operates a farm, says on the official "Idol" Web site that her "mommie" is both her "American Idol" and her "hero."

FOX is expecting a lot of eyeballs on "Idol" Tuesday night. Season four of the megahit is averaging nearly 28 million weekly viewers for Tuesday's performance broadcasts and more than 25 million for Wednesday's results half-hour, bettering last season by several million viewers, according to Nielsen Media Research.

This year's finale could be the show's biggest night ever — and the heat is on.

"Everybody keeps saying, 'Oh, Bo doesn't care, he doesn't want to win.' It's not really the case that I never wanted to win, it's more that I never really thought I had a chance," Bice told FOX News.

Will Bo be "Idol"'s "hair" apparent? Or will Carrie win the crown?

Either way, both are assured record deals, as coming in second on "Idol" has proven to be just as lucrative.

"Really good things happen to the top two, so I am really excited about whatever lies ahead, because I know it's gonna ... So many doors have opened for me, that I never thought I'd see, but it all been incredible," Underwood told FOX News.

FOX News' Lisa Bernhard, the New York Post's Michael Starr and the Associated Press contributed to this report.

"American Idol" airs on FOX Network, a property of News Corp. News Corp. is the parent company of FOX News Channel, which operates FOXNews.com.