Jessica Simpson‘s incredibly romantic wedding was this weekend — and once we stopped talking about the dress, the veil, the shoes and her very fancy wedding party, we (of course) had to discuss that hair.

Celebrity hair colorist Rita Hazan, who has been working with Simpson for about 15 years, gave us the exclusive scoop on how she got the star’s signature blonde strands sleek, shiny and absolutely perfect for her July 5 wedding to Eric Johnson.

To complement Simpson’s elegant champagne-colored Carolina Herrera gown, Hazan had only one option for the star: blonde. “Jessica just had to be blonde. She looks her best as a blonde,” Hazan tells PEOPLE exclusively.

And not just any shade of blonde: inspiration for the hue came directly from Simpson’s two-year-old daughter, Maxwell. “I wanted her hair to be timeless, so the color was more of a baby blonde [to match] Maxwell’s color, with subtle highlights that blend into her hair,” Hazan said.

To coordinate with the timing of the ceremony, Hazan began prepping Simpson’s tresses six months in advance by traveling to Los Angeles to do single process color and highlights each month. She made sure to schedule her final touch-up the week of the wedding for that perfectly glossy shade.

Hazan’s top priority? Creating dimension to ensure the color “didn’t look fake.” Hazan explains that each step in the coloring process is crucial in order to keep the color natural-looking — and to make sure that Simpson didn’t appear washed-out against her pale dress. “Highlight placement is important, and the tone is the most important. It has to be perfect: not too pale and not too golden,” she says.

To keep the hue intact before the big day, Hazan had Simpson apply the colorist’s own Ultimate Shine Color Gloss in “Breaking Brass” each time she shampooed, along with a conditioning treatment the week of the wedding.

With such extensive hair prep, it’s no wonder the star looked picture-perfect on her big day!

Source: People.com