Meghan Markle never really fitted in with the royal family that even Prince William and Kate Middleton seemingly refused to welcome and accept her.

Speaking with Express U.K. royal author Leslie Caroll revealed how the differences between Kate and Meghan made the brothers' relationship even more complicated than ever.

"William has not always felt warmly toward Meghan, he needs to accept that she's Harry's wife, the mother of their son, and the woman he adores-his soul mate," the royal author claimed.

For instance, Meghan once approached the Duke of Cambridge, but he just shrugged her offThe Sussexes fueled the issue more after they decided to split from the joint charity they shared with Cambridges through a statement released by the royal palace.

However, despite lying low, Meghan still failed to get the acceptance of her husband's brother and family.

The royal writer went on and divulged how the brothers grew apart when they married the two "very different" women. Harry and William also never had identical personalities or interests, making things between them even worse.

Their differences also prevented them from having a "warm relationship," most especially when they are both "fiercely protective" of their families.

If ever William wants to mend his relationship with his brother again, he has to approve his choices and reasons for making them, according to Carroll.

Where Did the Rift Stem?

The royal author also suggested that the gap between the once-close siblings was caused by the continuous defense of Harry over his marriage with Meghan from royal critics.

In the winter of 2018, rumors about the beginning of a royal feud started to emerge after Meghan allegedly made Kate cry.

Royal expert Katie Nicholl, however, highlighted that the Duke of Sussex blamed his brother for not putting some effort to embrace Meghan in the family.

"Harry felt William wasn't rolling out the red carpet for Meghan and told him so. They had a bit of a fall-out, which was only resolved when Charles stepped in and asked William to make an effort," the royal author disclosed.

Even Prince Charles and Queen Elizabeth II "worked incredibly hard to try and make sure everybody reunites." However, it was not successful at all as the brothers drifted further away from each other.

Until the last quarter of 2019, the rift continued and got worse when the Sussexes made an appearance on ITV's documentary "Harry & Meghan: An African Journey." From there, Harry finally broke his silence and admitted the fact that there is indeed a royal rift.

"Part of this role and part of this job, and this family, being under the pressure that it's under, inevitably, you know, stuff happens," the Duke of Sussex shared before claiming that they will always be brothers even when they take different paths at the moment.

Only time will tell if Prince William and Kate would still give Meghan a chance. But since the Sussexes has already decided to depart from the monarchy, it seems like the Fab Four will not be so fab any time in the near future.

READ MORE: Prince Harry Will BEG Royal Family to Accept Him Back Soon, Expert Claims