Transcript for Meghan Markle's mom meets Prince Harry's immediate family for first time
Reporter: This is likely the last glimpse of the royal couple together before they walk down the aisle at St. George's chapel in Windsor, driving into the 1,000-year-old castle for rehearsal, outside, a preview of the royal celebration complete with a practice run, the couple's horse-drawn carriage. It's not just trying to get it right, it's trying to get it right in front of the world's cameras. This is live. This is for real. And you're stepping into a drama that is part of the history of the world. So the pressure's on. Reporter: The couple poised under pressure despite Meghan Markle's family drama that threatens to overshadow the festivities. Dramatic twist in the royal wedding saga. He's in, he's out, rumors he might be in again. Her father reportedly cannot travel for the next week or two. Reporter: After days of conflicting reports, kensington palace finally confirming today Meghan's father, Thomas Markle, is no longer attending the wedding, reportedly recovering from heart surgery, and perhaps embarrassment after allegingly staging these infamous photos. Meghan in a rare move for a soon to be royal offering her own statement writing in part, I've always cared for my father and hope he can be given the space he needs to focus on his health. Every family has circumstances that are unknown to the world. I just feel bad for her that she won't have her dad. Reporter: The only member of Meghan's family scheduled to attend the wedding is her mother, Doria Ragland, today meeting prince Harry's family for the first time. She could be the one to walk Meghan down the aisle. She must be heartbroken, really. I think a mother will do a fantastic job and it's something different for the Royals. Is there a sense maybe that the palace hasn't really done enough to protect Meghan and her extended family, to try to prepare all these people for this huge amount of tabloid speculation? The mother lives in L.A., the father lives in Mexico. I'm not sure where the half brothers and sisters are. They're clearly making noise. It's obvious the markles did need more support. How would they know? Reporter: I sat down for tea with imogen Lloyd Webber, an authority on royal life, and Dai Montague, whoed into aristocracy. How ready do you think Meghan is for this level of Paparazzi, was she ready going into this? She's had Paparazzi around her because of "Suits." I think this level that's happening this week, it was distressing. As a bride, it's already stressful getting married. And the last thing you want to happen is to have your family make things bubble up. I think the royal family would hate to watch all this happening now. They will learn some lessons. One does wonder why the palace didn't make her family perhaps sign ndas, for instance, make sure me were okay financially, so forth. No one can prepare you for royal life. Reporter: The spectacle of this past week is just a taste of the scrutiny the 36-year-old will experience once she joins the royal family on Saturday. It's a goldfish bowl, at the end of the day. The queen mother described monarchy as an intolerable privilege. And it is that. Reporter: Becoming part of the British royal family was a jarring transformation for princess Diana, too. The shy 19-year-old nursery schoolteacher became the most-photographed woman in the world. She spoke about it during her famous bbc news panorama interview. I couldn't understand the level of interest. The media were everywhere. Here was a fairy story that everybody wanted to work. And so it was isolating. But it was also a situation where you couldn't indulge in feeling sorry for yourself, you had to either sink or swim. And you to learn that very fast. There are very few people who ever become members of the royal family. So there's no defined path. But it's very, very hard to maneuver in there. It's a minefield. Reporter: India hicks was one of princess diian yeah's bridesmaids. You're a princess, you're riding in carriages, the world's watching, you're a fashion sensation as well. Then those years pass. And suddenly you're in this world where there is very little privacy. And at times they probably feel quite caged. Reporter: While Meghan will likely live in kensington palace, and likely gain the royal title duchess over the weekend, her life won't necessarily be charmed. There's a world expectation upon your shoulders. I think most of us can't comprehend what that's like. I don't know how anybody prepares for that. Reporter: Alex debruss was officer of arms to the queen and consultant on films like "The king's speech." I will do anything in my power to keep my brother on the throne. There is the difficulty that if you decide you're going to go out, well, a number of people need to be told. Your personal protection officer. Your car needs to be available at the front door. It's probably been taken away by somebody to keep the front door looking tidy in case somebody comes to visit. Reporter: Prince Harry has been his fiancee's constant advocate, warning her of the pressures that come with this life. I've had some pretty frank conversations with her, what you're letting yourself in for, it's a big deal. And it's not -- it's not easy for anybody. But I know that at the end of the day, she choosesme. I choose her. And therefore, you know, whatever we have to tackle together or individually will always be us together as a team. So I think she's capable -- So nicely said, isn't it? She's capable of anything. Reporter: She may be capable of adapting, but sister-in-law Catherine Middleton was seemingly crafted for it. Kate went out and met members of the family over a long period, she understood what royal life was. Be able to learn from Kate. Clearly Kate has done an awful lot of these functions where you have to sit on nearly a throne, or you have to be on a royal tour, you're getting in and out of a car, getting on and off an airplane, your skirt flies up -- Reporter: Meghan and Kate are the next generation of royal sisters-in-law following in the footsteps of Diana and Sarah Ferguson. Diana was this sensation. That everybody was obsessed with. Sarah Ferguson, it's always harder to be slightly in the shadows, to be marrying the second in line to the throne. Because there's no defined role for her. And one hopes in the way that Diana did so well in finding causes that meant something to her. If Meghan isn to do that, I think she'll have a much easier ride than Sarah Ferguson did. Reporter: Many see Meghan as a much-needed dose of modernity. I think most people look at the royal family and think, most people don't like like that I don't have a butler. There's a story going around she's been hugging security guards. They're like, why are you hugging me? She's going, I'm American, I hug. I'm a hugger. There's something wonderfully endearing about that. Meghan has joined a family where it seems terribly excited to see a new arrival, particularly with the freshness an American brings to the somewhat stiff approach that the British are accused of having. And I think, you know, she'll refresh that. ?????? Reporter: As the preparations continue at Windsor castle, Harry and Meghan hoping the tabloids are behind them, embracing the mantra "Love conquers all." For "Nightline," James Longman at Windsor castle.
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