Don’t let Brittany Guidry’s glitzy gown, perfect makeup and well-coiffed hair fool you. She swears there’s a tomboy under there.

Although for the last several weeks the Houma 21-year-old and reigning Miss Louisiana USA has been in and out of hair salons and dress designers’ studios, that’s not really her “thing.”

“I’d rather be outside riding my bike or walking my dog (a boxer named Dash) or something,” Guidry said.

For the last two weeks, Guidry and contestants from the other 49 states and the District of Columbia have been in town preparing for tonight’s big event, the 2014 Miss USA Pageant.

“We’re going around Baton Rouge visiting different places, museums, doing TV news shows and radio shows,” Guidry said. “We’ll be in rehearsals a lot of the time. Since it is a live show we have to make sure that’s perfected.”

Tonight’s three-hour show televised from the River Center will feature evening gown, swimsuit and interview competitions. The winner will advance to the Miss Universe Pageant.

“I’m working out, of course,” Guidry said, in detailing her pageant prep work. “The swimsuit portion is a big factor in the competition. I’m going to see my hairstylist, practicing hairstyles, practicing makeup, making sure I have everything from a steamer, to Band-Aids, to bobby pins, so I don’t have to go out and get anything while I’m here.

“And I have to actually study, as weird as that sounds, because I have to stay on top of current events and things like that, because I have to prepare for interview and top 5 question.”

Contestants’ swimwear, from designer Kandice Pelletier, is provided by the pageant, and the shoes they wear with their swimsuits come from Chinese Laundry.

“I’m required to get my evening gown and interview outfit, so I’ve had a custom evening gown designed by Sherri Hill for the show and custom interview (outfit) by Gregory Ellenburg,” she said.

In addition, Guidry has three clothing sponsors ­— Maven WomensWear, Chatta Box and Show Me Your Mumu ­— filling out the rest of her wardrobe.

By die-hard pageant mom standards, Guidry, the daughter of Vickie and Craig Guidry, of Houma, is a latecomer to the party.

“I didn’t start pageants until I was 14,” she said. “I did two smaller pageants before I competed in the Miss USA system, and then from there, I did Miss Teen Lafayette in 2008 and I got that, and that was my ticket to go to state that year. So I went and won Miss Teen Louisiana 2009. And then I hadn’t been back until Miss Florida Parishes (where her win qualified her for Miss Louisiana). I had a nice five-year break.”

The Vandebilt Catholic High School graduate also is taking a breather from her studies at the University of Louisiana at Lafayette, where she’s pursuing a degree in public relations. Right now she’s working on modeling opportunities, the pageants and her charity work with the USO (United Service Organizations).

“With the USO, I have been traveling back and forth to New York,” Guidry said. “I just did a fashion show where (designer) Sherri Hill partnered with the USO, and donated over $400,000 in dresses to military daughters for prom, so that was a really cool event we got to go to because we got to help the girls pick out their prom dresses.

“I’m getting goose bumps just talking about it. It was a very humbling experience and one that I will never forget.”

Guidry said she ran her first 5K, with the USO and some other military personnel, when the USS New York was docked in the Big Apple in November.

“I was the only state titleholder to be on the ship, but the ship was actually made in Louisiana, with steel from the Twin Towers,” she said.

Guidry has also worked with Trafficking Hope, Lemonade Day and Toys for Tots.

Were she to win the Miss USA title, Guidry said she’d also be a spokeswoman for breast and ovarian cancer organizations as well as Best Buddies, but would continue her work with the USO.

“You define the crown; the crown doesn’t define you,” she said, of what her titles mean to her. “You just have to be the best version of you that you can be, and you have to truly know yourself to be able to fulfill a title, I think, the way that it should be. That’s all through positive self-talk and loving yourself, and being confident.”