First Look: See Actress Jeanna de Waal in Character as Princess Diana in New Broadway Musical

Princess Diana is officially on Broadway.

On Monday night, the curtains went up for the first preview of Diana: A True Musical Story — and outside the Longacre Theater, Jeanna de Waal was treated like true royalty. The actress, who is stepping into the shoes of Princess Diana, signed autographs for eager fans, some of whom waved Union Jack flags and sported tiaras as the crowd spilled into West 48th Street.

But de Waal was just a young child when Princess Diana died, so the task of bringing the beloved international icon to the Broadway stage meant hours of “devouring” YouTube videos — everything from the princess in interviews to an eight-minute clip of Diana in mom mode with Prince William and Prince Harry.

“She’s not speaking, but you can see the way that she’s caring for Harry and William, and how she relates to them. How she watches so intensely,” the actress, who previously starred in Kinky Boots and American Idiot on the Great White Way, tells PEOPLE in this week’s issue. “She doesn’t seem distracted by anything. She’s very present in every single moment that she’s involved with.”

The challenges of playing someone instantly recognized around the world involved more than just mastering her mannerisms, however.

“People, within like 2 seconds of seeing you, are going to decide: they either buy it or they don’t,” says de Waal. “If they don’t buy it, it’s going to be hard for them to enjoy the story and get lost in it.”

The show’s star shares Princess Diana’s British accent, but de Waal says that’s about all they had in common.

“[Diana] had this amazing grace about her that I definitely don’t have naturally,” she says. “It’s been a real process on how to control my body and move in the way she moved.”

Making matters even more difficult is that de Waal is not nearly as tall as the royal, who stood at 5’10” — a fact that reportedly made Prince Charles self conscious. The team has made up for the difference with cleverly hidden platforms in the actress’s heels and plenty of body work.

“You really can sort of fake that you’re a little bit taller by the way you carry yourself,” de Waal says.

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Opening night for the musical is March 31 — the same day that Prince Harry and Meghan Markle will officially step down from their roles as senior members of the royal family. The couple’s openness about the headline-making exit stems directly from the straightforward communication that Princess Diana brought to the family.

“This is expected transparency now, which didn’t exist pre-Diana,” notes de Waal. “The expectation for the royal family to explain what’s going on and talk very candidly and show these people more emotional moments in their lives. All of those aspects were not part of the dynamic before Diana.”