Transforming into Barbie isn't as easy as it looks.

Margot Robbie, who plays the iconic doll in Greta Gerwig's upcoming Barbie movie, has continued to channel her character IRL during the international press tour. But nailing the toy's glamorous getups isn't for the faint of heart. Just ask the actress' hair colorist Jacob Schwartz, who revealed the lengthy process that goes into achieving her signature Barbie blonde mane.

"Margot's hair is far from a Barbie doll's," Jacob exclusively told E! News, "which is why it's my priority to keep her hair looking natural, effortless and true to her."

So, how does the haircare expert give the Babylon star a shiny golden color without damaging her tresses? 

"I choose specific fine pieces throughout her entire head of hair," he explained. "I weave a certain amount of highlights on different parts of the base, as opposed to bleaching her entire head of hair." 

Jacob is also particular about the products he uses to color Margot's strands.

"The secret is using a high-quality bleach," he put it simply, "ones that not only have bonding agents inside, which create a protective layer around the hair bonds during the color process and reduce hair damage, but one that has a chelating agent."

Why are chelating agents important? According to Jacob it "helps capture and neutralize metal ions in the hair which minimizes hair breakage to ensure soft and healthy-looking hair."

When it comes to the products Jacob uses, his go-tos are Schwarzkopf Professional's Blondme Premium Lightener 9+ and the brand's Blondme All Blondes Rich Shampoo and Conditioner.

"Blonde is one of the most complicated colors to achieve," the celebrity hair colorist noted. "That's why I always send Margot home with Blondme Care because it's designed to work together with Blondme Color products and helps stabilize her hair structure for long-lasting strength to withstand all her red carpet looks."

And while it's not all fun and games to be blonde, what's clear is that hair plays a key role in Margot's fabulous fashion moments.

Case in point? For the Barbie movie's Los Angeles premiere on July 9, she recreated the toy's 1960 Solo in the Spotlight look. Her custom Schiaparelli Haute Couture black strapless dress featured sequin and a ruffled tulle hemline with a bright red rose adornment. She paired the look with black velvet opera-length gloves, coordinating mule slides, a massive diamond choker necklace and baby pink scarf.

As for her glam? Margot didn't miss a beat, rocking a bold red lip with the rosiest of cheeks and a dainty cat-eye. The perfect finishing touch, her slick ponytail reminiscent of a pin-up.

"Hair is contingent on the success of any look," Jacob shared. "More specifically, our association and enduring fascination with Barbie lies in her impossibly perfect glamour."

It's safe to say Margot's Barbie-inspired style is perfect on and off the screen.

Relive some of her best fashion moments that could've been pulled straight from Barbie's closet. And to get more insight from the actress herself on the summer blockbuster, tune in to E! News tonight, July 10 at 11 p.m.