Meghan Markle and Prince Harry are reportedly triggered by comparisons to the royal family.
Speaking on his YouTube channel, royal expert Neil Sean claimed: "According to a very good source in Montecito, and as ever we say allegedly, basically Meghan and Harry can't understand the difference between what they did with Ellen, particularly, you know, when Prince Harry was making fun in the orange outfit, trying to promote the Invictus Games.
"What's the difference, they are just showing a fun side, trying to market themselves, and of course get their projects off the ground".
Mr Sean added: "They are non-royals so what difference does it make.
"How is different for the future King and Queen Consort [Prince Charles and Camilla] of England, Scotland, Ireland, and of course, Wales to be doing this sort of thing.
He continued: "There is a vast difference when they think about it.
"They're [Charles and Camilla] not doing it for money, they're doing it basically to raise profile and to show a fun side.
"It's nothing about business, it's about a reality, soaps [are] meant to show partly a reality".
He added: "A lot of the [Eastenders] stars were thrilled, of course, the show will get a lot of ratings based on this and most importantly, of course, there's no fee at the end of it".
Mr Sean pointed out: "Meghan and Harry's team, as ever, are very quick, as we ever we have to say allegedly, to downplay fun things that the British monarchy are doing.
He went on to mention Prince William and Kate's latest outing to the Top Gun premiere.
Mr Sean concluded: "A close, very close, a source tells me that they're [Meghan and Harry] very kind of mismade [at the] way that whatever they do is seen as negative, bad and basically trashy, whilst something similar, you know it could be Charles and Camilla, it's lauded, it's applauded and that's the baffling bit.
"Particularly, that Prince Harry doesn't seemingly doesn't understand".