Julie Montagu, an American who became Viscountess Hinchingbrooke when she married into British aristocracy, isn’t surprised Meghan Markle and Prince Harry took a "step back" as senior royals.

The Duke and Duchess of Sussex are currently residing in Markle’s native Los Angeles with their son Archie, 1.

Montagu is married to Luke Timothy Charles Montagu, Viscount Hinchingbrooke and son of the 11th Earl of Sandwich. The mother of four is currently starring in Smithsonian Channel’s “An American Aristocrat’s Guide to Great Estates,” where the Illinois native tours some of the U.K.’s most important and historic homes. And when she’s not on camera, the 46-year-old is helping her husband run the family estate in Dorset -- 16th-century Mapperton House.

The “Ladies of London” alum spoke to Fox News about Markle, 38, and Harry, 35 leaving the U.K., filming her TV series, and the American mannerisms that continue to surprise Brits.

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Prince Harry, Duke of Sussex and Meghan, Duchess of Sussex attend The Endeavour Fund Awards at Mansion House on March 05, 2020, in London, England.

Prince Harry, Duke of Sussex and Meghan, Duchess of Sussex attend The Endeavour Fund Awards at Mansion House on March 05, 2020, in London, England. (Photo by Samir Hussein/WireImage/Getty)

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Fox News: What advice would you give to Prince Harry, a royal not living in a great British estate these days, but rather in Los Angeles?
Julie Montagu: Well, I think that Harry was always the rebel, wasn't he? He probably is preferring that life. He's not hounded by the press. He's been hounded his entire life. He's finally being, for the most part, being left alone and he gets to live this laid back life. They just do what they want to do.

Fox News: Does it surprise you that Meghan Markle moved back to the United States?
Montagu: Does it surprise me? No. She was getting such really relentless negative press from the British tabloid press. It doesn't surprise me at all. I think they had enough. And we saw what happened to Princess Diana. And I think the last thing that Harry wanted to happen was the exact same thing that happened to his mother. So, I think that they really gave it a good go. I mean, I was there, I read all the articles.

Fox News: Are there any American customs or mannerisms that continued to surprise Brits even after your years living in the U.K.?
Montagu: Yeah. I mean, every day. I still have to say to my kids sometimes over the phone, "Can you say it in the American way?" because I can't understand you when you say it in the English way. So there's still ... It's such a difference between American words and English words that I think that a lot of people forget that I thought when I moved over here, "Oh, we all speak the same language."

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There are so many words like you would never say fanny pack, ever. Fanny is like a bad word over here. You would never say silverware. You would say cutlery. Silverware is for a really formal dinner and you actually get out the silver, you would call it cutlery… I mean, I could go on and on and on. Flashlight is torch. Pants or trousers. Sat nav is GPS over in America. Yeah, we could spend an hour on that.

Fox News: What can audiences expect from a show like “An American Aristocrat’s Guide to Great Estates”?
Montagu: So for Americans, they can expect to see something that they wouldn't necessarily ever get on a tour if they were to actually visit these homes themselves. I really go into how these homes make themselves commercially viable. So it's very different from just getting a tour of the historical part of the house. I really look at what these homes are doing to make sure that their visitors keep coming back for their special events, the biomass boiler, what they've been installed in order to heat these enormous homes.

Most of these homes when they were built would have one bath and hardly any hot water. And so looking at how they heat the homes, but also at the same time, how they are a community. So remember these homes were built as sort of the center of the community. And so in particular, episode one is all about the Highland Games and really how that such a community that Inveraray Castle does, the Duke and the Duchess of Argyll, and making it a community event. And, it's wonderful.

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Julie Montagu on her wedding day.

Julie Montagu on her wedding day. (Courtesy of Julie Montagu.)

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Fox News: You, an all-American girl from Sugar Grove, now live in your husband's historic family estate in Dorset. What does it take to run that home?
Montagu: It’s a lot of work. I can't even begin to tell you. I'm in the house right now. It's 500 years old and we have constant leaks, we have constant repairs because this is what's considered a grade one listed home. And most of the homes that you'll see on the show are as well, which means that it's of extraordinary history.

So you can't do much to these homes apart from fixing them and repair them. And you have to repair them a certain way to keep it in line with heritage, so it's a lot of work. During the pandemic, we've obviously, it's a historic home that we live in, but it's our business and we've had to furlough everybody, so my husband has become very good at fixing leaks.

And we pretty much spend most of our day in this home sort of fixing it and making sure that it's OK. I would say our workday is about 12 hours a day, seven days a week from recently.

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Fox News: So in other words, it's definitely not the type of fairy tale that one would expect.
Montagu: No. If you watched "Downton Abbey," it's the farthest thing. Long gone are the days of "Downton Abbey." [But] I really get stuck in. I'm American, we have this work ethic that we were all born with.

So I get very much stuck in and I'm a doer so I'm constantly working and doing and coming up with creative ideas to bring more visitors to come to see ... The name of our house is Mapperton House, which is considered England's finest manor house. So again, I'm an American, a hard worker, definitely.

Fox News: Which estate surprised you the most and why?
Montagu: I would probably say that the one that surprised me the most, oh, gosh, they all surprised me. They're all hard workers. That's a tough question to be perfectly honest. I think it's hard to say which one surprised me the most because I think they all surprised me because I think I went in there and quite naive thinking that everybody was doing the same thing, opening up their house to the public, trying to get as many visitors in, and then having tons of weddings.

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Whereas, yes, they're all trying to do that and so much more. So whether it's beekeeping or steam engine, or I got to play cricket, I totally did it the wrong way. I was batting like an American. And also, having events that they invited the local community to such as sculpture, a gallery walk within the estate.

So they all do something different. They all just work so incredibly hard to keep their house in the family because it's not a national trust home. It's a lived-in home. And the second it becomes a national trust home is when it becomes a museum, nobody lives in the house anymore. So that's what makes these homes extra special, they're a home, but also they have these wonderful homeowners and only they are the ones who can tell the history as we know it.

"An American Aristocrat's Guide to Great Estates" airs Sunday, May 24 at 9 p.m. on the Smithsonian Channel.