Now, rumours have suggested the newly minted Duchess of Sussex has "changed" Harry which has strained his relationship with Kate.
A source told The Mail on Sunday: “Kate and Harry have always had a very close relationship, but she said things were different.
“Meghan’s a strong character and so is Kate, so it doesn’t surprise me there have been clashes.”
According to reports, Kate and Will had tried to warm up to Meghan last year when they were asked by Prince Charles to invite her and Harry to Anmer Hall in Sandringham.
It is reported that the meeting did not bring the couples closer together and was instead spoiled by a “ghastly row”.
A senior royal aide spilled things became sour when the pregnant royal was judged to be "downright rude."
The aide told The Mail on Sunday: “Kate had a quiet word with Meghan. It escalated rapidly after Meghan complained to Harry that she had been ‘told off’.
“He took her side, while William defended Kate, who was five months pregnant with Louis and certainly didn’t want this sort of confrontation.”
Prince William had also reportedly voiced concerns about his brother’s bride ahead of the wedding.
“The problem is that the Cambridges felt things had moved very quickly between Harry and Meghan," the source added.
“Wills particularly was worried and felt close enough to Harry to voice his thoughts.”
The news comes after it was confirmed the Duke and Duchess of Sussex had decided to move from Kensington Palace to Windsor's Frogmore Cottage.