When you're a fashion chameleon like Rihanna, you keep your closet close -- and your hairstylist even closer.

We caught up with the architect of RiRi's ever-changing hair looks over breakfast at Norma's in New York, where Ursula Stephen was catching a well-deserved breather after prepping her star client for a movie shoot, the Grammys and a music video for new single "S&M."

"Rihanna had all kinds of crazy ideas for that video, and I went all out, buying like six different wigs, coloring them, cutting them. Music videos are usually my least favorite to do because there is so much pressure and such a rush, and then they wear the look for like two minutes. But this was a creative challenge for me, so I loved it," Stephen told StyleList.

In fact, wigs are often behind the drastic and dramatic looks we see from Rihanna, according to Stephen. Not only do wigs style better with rollers and hot irons, but stylists like Stephen use wigs to preserve the health of their celeb clients' hair, which would otherwise suffer irreparable damage.

Gwen Stefani's longtime stylist, Danilo, recently told us backstage at New York Fashion Week that he also uses hair pieces to spare Stefani's platinum-blond locks from the wrath of heat styling.

"I call it bouffantry. Instead of burning a crimp into your hair or teasing it past breaking point, just buy a piece of hair and style that instead," Danilo told us before the L.A.M.B. Fall 2011 fashion show.

Stephen says that Rihanna so loved one lioness-like mane of outrageously frizzy curls, that she insisted on taking it with her on vacation directly after the shoot.

"I was like, 'Bring me that wig and let me cut it down for you to wear out.' But she wouldn't let me touch it! She loves making a statement with her hair," laughed Stephen.

The 32-year-old Brooklyn native says she shops both high- and low-end beauty-supply stores for Rihanna's hairpieces.

Trips range from high-end places like L.A.'s The Hair Shop, where wigs can cost anywhere from $600 to upward of $2,000, all the way down to her favorite haunts on Flatbush Ave. in Brooklyn, which Stephen has frequented since her cosmetology school days.

At those beauty-supply shops, a wig that costs $20 to $70 has an equal chance of making it into a music video or onto a red carpet as the $1,000 versions.

"It's not about the cost, or even if it's synthetic or real hair. It's about the style you want first. You have to have your vision, then you go and find the piece. The only thing I'd say is a better choice is to go with synthetic hair if you want a real curly style. It holds much better," said Stephen.

From the latest "matador red" look to bowl cuts and rambunctious curls, Rihanna's hair often garners more criticism than praise in the press. Yet Stephen explained that hair often has to work just as hard as the talent.

"People say to me, 'Why did you make her hair so big? Why is it so crazy out there?' But you have to understand: She's a performer. She can't just walk around with some little ponytail. She has to perform. She has to have an image. The hair even helps her get into the character of whatever she's doing," said Stephen.

No matter what the style, color or look Rihanna is strutting on the red carpet, Stephen said the finishing touch is always an all-over shine spray right before Rihanna steps out to take her spin.

Lately, she has been using Motions Hold & Shine Styling Spray, a new product that combines humidity-resistant hold with a light glasslike misting. Retailing for $3.99 to $4.99, the large can is available at drugstores nationwide.

"The Motions line is targeted to ethnic hair, but I use the spray on all hair types to get lots of shine," revealed Stephen.

As for where she gets inspiration for the often envelope-pushing visions she creates for Rihanna, Stephen says most ideas come straight from the fashion runways of the world, in addition to style-savvy hotspots the two travel to often, like Japan.

"It's always about collaboration with a team -- the makeup artist, the stylist -- and what Rihanna is feelin' that day. What's her mood? What image does she want? When I see a celeb have an 'off' night on the red carpet, I assume it's a breakdown of the team somewhere, that they aren't working together," says Stephen.

Up next for Rihanna is a supporting role in "Battleship," a science fiction thriller that has the star dressed down in camouflage, a short brown cut and sporting a cap for most of the movie.

"The director, Peter Berg, took the cap off for a scene, but put it back on because he said she looked too pretty without it. I gotta tell you the truth: As a hairstylist, I was snoozing for much of the filming," said Stephen.

We're going to suggest Stephen set her alarm clock, because it's just a matter of time before RiRi is ready for her next reinvention.

To see Rihanna's hair evolution over the past year, check out our gallery.