Activist and actress: Meghan Markle before she met Prince Harry

Last Updated May 18, 2018 2:04 PM EDT

When Meghan Markle says "I do" to Prince Harry at Windsor Castle on Saturday, she will become the first American to marry into the British royal family since 1937. Markle's life may seem like an unlikely fairytale, but those who knew her before her engagement to Prince Harry say she's always had that something.

"She's someone that everybody knew, 'cause she was just a really warm, wonderful person, with a really welcoming energy. And also, just a remarkably beautiful person on the outside as well," sorority sister Jax Tranchida said.
 
As an international studies and theater major at Northwestern University, Markle launched her acting career. One of her earliest roles was in the romantic comedy starring Ashton Kutcher, "A Lot Like Love." In 2011, Markle debuted in the series "Suits" as a paralegal-turned-attorney. 

"The first time I met Meghan Markle she came into the room to cast for the role of Rachel on 'Suits.' And we were at the end of our day and we were exhausted and ... she came in and she read. And she blew us away," "Suits" director Kevin Bray said.

After a seven-season run, Markle made her last appearance on the show. In the finale, she marries her longtime love interest and is given away at the wedding by her father, played by Wendell Pierce.

"You think that's a co-inkydink that the series decided… to split it up that way?" King asked him, laughing.
 
"I think it's really interesting that the network looked at the schedule and the calendar and, by coincidence, her last episodes happen to coincide with the build-up to the royal wedding," Pierce said.

Before her acting career, at age 12, Markle became an activist after seeing a dish soap commercial she felt was sexist. She decided to write a letter to voice her concerns.

"She said that the little boys in her class began to tease the girls and say, 'Well, you know, that's all you're good for. That's what girls do, is girls do dishes,'" TV host Linda Ellerbee said.  

"It makes me feel like they're going to grow up thinking that girls are less than them," a young Markle said.
  
"She said to me in her letter, 'While I don't think this is sexual harassment, I think this is how these attitudes get started,' which was a very clever leap to make. Because she is right, of course," Ellerbee said. 

Her passion for advocacy stuck. In 2016, Markle traveled to Rwanda to expand access to clean water in rural areas.

"When you meet Meghan, you're struck immediately by how very intelligent she is. ... We didn't have conversations that were superficial about the causes that moved her or the experience of children around the world or global issues of any variety," said Lara Dewar, chief marketing and development officer for World Vision Canada. "When she gets engaged in a cause, she brings a real curiosity to that cause. So she asks a lot of questions." 

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Though she has retired from her acting career to focus on royal duties, the world will be tuned in to see what lies ahead for the future royal. 

"She is a modern day Grace Kelly, you know? This American actor who fell in love with a prince, gave up her career because she was going on an adventure that no role could ever live up to in fantasy. Her reality is surpassing any sort of dream that she had," Pierce said.