Transcript for How Meghan Markle will carry on Princess Diana's legacy

We are here, prince Harry and Meghan Markle will say "I do." That's less than two days from now and after the ceremony is when begins as a member of the royal family. The question is how will she compare to the people's princess, princess Diana? Paula, you have taken a closer look. We did. One of the things that initially drew Harry to Meghan was her love of charity. Her altruism and philanthropy. She was the people's princess. The most photographed woman in the world. Princess Diana was adored by people from every corner of the globe and now as Meghan Markle prepares to become her royal highness, princess Henry of Wales, the world is falling in love with the newest face of the royal family. Meghan like Diana is beautiful and bold with a flare for fashion. It was amazing how the world reacted to what she wore. She became this design icon. Reporter: Diana's own approach to being a royal was ahead of her time. She was regal but at the same time she was able to be approachable. She was emotionally articulate. Reporter: It is that compassionate advocacy that is perhaps the late princess' greatest legacy. I'm trying to highlight a problem that's going on all around the world. Reporter: She is widely admired for alleviating the stigma of Ades with just a single photo. That is no question that Meghan and Harry will use their profile to champion causes that may be controversial in exactly the same way as princess Diana did. If she can go on and follow what? Diana's steps of being able to get the world to watch her, to follow her and to learn from her, it would be exceptional. Reporter: Markle a U.N. Ambassador has already made her mark as a humanitarian. One of the things that really attracted Harry to her, Meghan is someone who like Diana leads with the heart, who isn't afraid to speak her mind. Reporter: When they say I do on Saturday, Meghan and Harry will become the latest royal couple to represent the crown. Meghan has this remarkable story of her own success that and her diverse background. All of these things will help continue to make the monarchy relevant. Reporter: With millions watching across the globe, one person's presence will be missed but the young couple believes Diana will be there in spirit. Without question, I think she will be over the moon with everything else going on I'm sure she's -- She's with us. She's with us, yeah. And Diana's presence will really be felt on the big day, even with little things like white flowers which were her favorite. If you notice the way he refers to his mother most of the time it's very much in the present sense. It's I can still feel her hugs and all I want, he says, is to make her proud and he says she's right there jumping up and down with joy. What an amazing relationship that they had. It's endearing. Still obviously you can see her influence on him, it's still there. We will bring in our royal contributor, imogen Lloyd Webber will join us now. Imogen, we heard princess Diana was called the people's princess. How will Meghan appeal to everyday people in her own way go she has that magnetic presence, doesn't she like Diana did. She's also beautiful. On some levels we can't relate to the royal family. Meghan is gorgeous and thin and beautiful, you know, and the royal family infrastructure is all around her but people relate to her in that she's self-made. A self-proclaimed feminist, biracial. Something different. Monarchy to survive has to adapt over time. It's always modernizing but never modern and Meghan is the latest face of that. I think a lot of people have questions is how will she fit? She is a humanitarian but also a feminist, she is an activist. That usually doesn't happen in the royal family. How will they handle it. They are supposed to be above politic answer put a spotlight on good causes and the queen has no leeway. But prince Charles has occasionally sort of gone after hot button issues so he'll definitely be able to guide Meghan as will William and Harry who have been less controversial than prince Charles and princess Diana and seem to have navigated a little better. All of that support will be there for Meghan and you learn the lessons of the past after Diana's death and, you know, people providing more support for her. How has Meghan already followed in some ways in the footsteps of princess Diana. She traveled to Afghanistan. She travelled to Rwanda and to India, Delhi, Mumbai for her cause and very much a humanitarian which is one of the reasons Harry fell in love with her.

This transcript has been automatically generated and may not be 100% accurate.