The Crushing Reason Queen Elizabeth I Caked Her Face with White Makeup

"We're left with this mask-like version of a person," actress Margot Robbie, who plays Queen Elizabeth I in Mary Queen of Scots, tells PEOPLE

Queen Elizabeth I's stark white-painted face and bold red wig remain part of her legacy, even centuries later.

In the latest exploration of her fascinating story, the new film Mary Queen of Scots, Margot Robbie is nearly unrecognizable as Elizabeth.

"It wasn't something that wasn't written into the script and something I wasn't really expecting when signing on for the role, but I was excited by the prospect," Robbie, 28, tells PEOPLE in this week's issue of embracing Elizabeth's striking style. "It helps me a lot to find a character if I look completely different to how I look in real life. It makes my acting job much easier."

Focus Features

A portrait of Queen Elizabeth I circa 1588. Ann Ronan Pictures/Print Collector/Getty

As for why Elizabeth sported such an unnatural appearance, it was a result of her coming down with smallpox in 1562. Elizabeth nearly died from the disease, and her skin was scarred from the illness, so she covered the pockmarks with heavy white makeup made of white lead and vinegar, which slowly poisoned her over time.

"When your skin isn't at its best, when you've got a breakout, you try and cover that up," says Mary Queen of Scots director Josie Rourke. "Do you feel confident enough to go into a meeting if you've got a gigantic blemish on your face? You can really feel her courage in really gathering herself back together again and finding the braveness to walk into those rooms."

Robbie as Elizabeth in Mary Queen of Scots. Liam Daniel/Focus Features

Robbie also notes that the makeup ultimately became part of Elizabeth's brutally self-disciplined persona.

"We're left with this mask-like version of a person, who is no longer a person by the end, but a throne and a representation of power in a country," she says. "I loved that she kind of built the mask for herself and then was inherently trapped by it."

Mary Queen of Scots hits theaters Friday.