Harry's mother, a humanitarian known to the world as "the People's Princess," died in a car crash in 1997 at just 36 years old. She left behind a rich legacy of humanitarian and advocacy work and is widely admired for alleviating the stigma surrounding AIDS when photos of her shaking hands with AIDS patients were published by the media.
"Diana blew out of the water all those prejudices with one small action," ABC News' royal contributor Victoria Murphy said. "There is no question that Meghan and Harry will champion causes that may be controversial ... in exactly the same way as Princess Diana did."
India Hicks, who was one of Princess Diana's bridesmaids in 1981 when the late princess married Charles Spencer, said that she sees the same passion Diana had for humanitarian work in her soon-to-be daughter-in-law, Markle.
"We see that in Meghan, that she has this passion as well," Hicks told ABC News. "Thank goodness, it's brilliant."
"And I think if she can go on and follow somewhat in Diana's steps of being able to get the world to watch her, to follow her, and to learn from her, would be exceptional," Hicks added.
Markle, a U.N. advocate for women, has already demonstrated her passion for humanitarian work, and a close friend of Markle said that this bond is how Markle and Harry initially fell in love.
"One of the things that really attracted Harry to her was what she's like on the inside," Murphy said. "Meghan is someone who, like Diana, is so strong-willed in her beliefs, who leads with the heart, who isn't afraid to speak her mind."
The former private secretary to the late Princess Diana, Patrick Jephson said, that like Diana, Markle is already breaking down barriers within the British monarchy.
"Meghan has this remarkable story of her own success ... and her diverse background," he said. "All of these things will help continue to make the monarchy relevant."
Even Harry said he think his late mother would've gotten along well with Markle.
"Oh they'd be thick as thieves, without question. I think she would be over the moon," Harry said in an interview with the BBC shortly after the couple announced their engagement.
He added that he thinks his mom "would have probably been best friends ... best friends with Meghan."
Markle added she thinks, "she's with us."