MEGHAN Markle will use her pregnancy to gain a "medieval power" over the royal family at Christmas, an author has claimed.

The royal watcher also claimed Kate Middleton is jealous of the Duchess of Sussex's successful career amid rumours of an awkward rift between the pair.

Alison James, who has written many books on the royal family, said fiercely independent Meghan is willing to fight for power in the family and will assert herself to be next to the queen.

Next week will be 37-year-old Meghan's second Christmas with the Windsors, but her first as an official part of the family.

Mrs James, who is an expert on royal pregnancies down the ages, said women in Medieval times became the powerful matriarch when carrying a child and were waited on hand and foot.

She predicts the Duchess will use this "Medieval power" to climb up the royal hierarchy.

And Mrs James said the new royal won't toe the line during her stay at Sandringham - claiming she will be the last to arrive and the first to leave.

She told The Sun Online: "Meghan does exactly what she wants - and Harry is besotted so lets her get away with it.

"She won't part in the drinking and thinks playing charades is stupid."

Growing up in Los Angeles Meg would often have Burger King for Christmas dinner and volunteer with the needy.

She faces a very different Christmas this year and will have to navigate a number of alien traditions with 'the Firm'.

Members of royal family, who can obviously afford whatever they like, give each other joke gifts, exchanged on Christmas Eve.

Alison suspects the Duchess of Sussex will struggle with the concept - much like her late mother-in-law.

At Princess Diana's first royal Christmas she was met with humiliation when she gave each member of the family a posh cashmere sweater, entirely missing the joke.

The self-deprecating English humour could be lost on the American too, according to Alison who says: "She’ll probably get them meditation mats or something."

Our expert also says the Suits actress will cause tension with her aversion to shooting - and has banned Prince Harry from taking part in the traditional Boxing Day shoot.

Meghan is said to disapprove of this British tradition, unlike the Middleton family, who love shooting and the opportunity to take part in royal shooting trips with the queen.

Alison said: "This will cause tensions between Kate and Meghan as they see the traditions so differently.

"Meghan is more independent as she had her own career before even becoming a part of the royal family.

"Kate is jealous because she never had that - all she did was some photography for her mum’s shop.

"She’s also jealous because she doesn’t have the courage to rebel like Meghan does."

Rumours of a rift between the Cambridges and the Sussexes have been swirling since The Sun revealed Harry and Meg were moving away from Kate and his brother last month.

Numerous sources have suggested the royal wives don't get on.

An insider revealed in November that Meghan had made Kate cry during a dress-fitting for the Duchess of Sussex's wedding.

Sources said the "stressful" fitting became too much for "emotional" Kate, who had just given birth to her third child, Louis.

Body language experts have since analysed encounters between the duchesses and detected a coolness between the pair.

This has raised concerns that Meghan has struggled to fit into the royal circle, and her own family dramas certainly won't have helped.

Alison said: "People seem to struggle to warm to her because of the way she’s treated her own father.

"I can’t see how they will carry on like that - especially on a family occasion like Christmas. She’s abandoned her family."

Meghan and her dad Thomas Markle have experienced difficulty throughout the process of her joining the Windsor family.

The pair have reportedly not spoken since her marriage to Prince Harry, an occasion he was not invited to.

Thomas spoke out on Good Morning Britain earlier this month, after she "ghosted" him.

He said: "She has always been a very controlling person and that is part of her nature but she has never been rude.

"The ghosting I don't completely understand - she's always been in charge, that's her nature, but not been rude."

But Alison says it's hardly surprising the ambitious woman readily ousted members of her immediate family from her life, claiming "she learnt it from Hollywood - it's hardwired in her DNA".

She says it isn't the first time Meghan has stepped on those close to her to climb the social ladder.

According to Alison Meghan is "quick to abandon friends without a backwards glance", and says this is what happened to her best friend when she criticised Meghan for the way she split up with her ex-husband.

In a scathing remark Alison said: "Meghan’s not especially talented so she had to force her way into Hollywood and leave people behind.

"Now she’s done the same to come into the royal family."

Leaving her old family behind, this year Meghan will spend her second Christmas with the royal family - a far cry from the family festivities of her youth in Los Angeles.

Meghan used to spend advent volunteering in soup kitchen and giving out turkeys to those who could not afford them.

However expert Alison says she can't see the Duchess of Sussex volunteering this year and jokes about the sight of seeing her "going round Windsor and giving to the poor".

She adds: "Meghan's hardly been slow on the uptake of coming forward and embracing the garb. She spends loads of money on clothes.

"Plus she'll enjoy having her feet up. She'll say 'I do a lot anyway and plus I'm pregnant'."

Kensington Palace declined to comment.