Rumours of a rift between the duchesses swirled after royal sources revealed emotional Kate, 36, ended up weeping.
An insider claimed the incident followed a “stressful” dress fitting — just weeks before Meghan, 37, married Prince Harry.
Royal aides did not deny the incident had taken place, amid claims that the duchesses are “very different people”.
Princess Charlotte, three, had been trying on her outfit just weeks before Meghan’s wedding to Prince Harry
Meghan, 37, is understood to have insisted on “the very best” for her big day — but the fitting did not go according to her demands.
Royal sources said the pressure of the “stressful” fitting became too much for her now sister-in-law, and that Duchess of Cambridge Kate was left shaken and in tears.
An insider told the Daily Telegraph: “Kate had only just given birth to her third child, Prince Louis, and was feeling quite emotional.”
The reported incident sparked rumours of a rift between Kate and the Duchess of Sussex.
The duchesses are understood to have put the incident behind them.
The two made their first appearance together a month after May’s Royal Wedding at an event in Cheshire.
And they both appeared — on separate balconies — during this month’s Remembrance Day commemorations.
Concerns have surfaced that American actress Meghan has at times struggled to fit into royal circles.
Sources claimed she regularly “bombarded” staff with early morning calls and emails.
Meghan’s PA Melissa Touabti — who previously worked for Robbie Williams and his fellow X Factor judge wife Ayda Field — has quit just six months after the wedding.
Melissa, 39, refused to comment on her departure.
On Saturday, The Sun revealed Meghan and husband Prince Harry were moving away from his brother and Kate, 36, in London.
The Duke and Duchess of Sussex have been living in Nottingham Cottage at Kensington Palace, where William and Kate also live. They are moving to Frogmore Cottage in the grounds of Windsor Castle in Berkshire.
We also revealed this month how the Queen was forced to intervene after Meghan upset royal aides over her demands to wear an emerald tiara for the wedding.
Meghan was told she had to wear another picked by the monarch.
The row escalated to such a degree that Her Majesty had to step in with a firm word in grandson Harry’s ear.
A book by royal commentator Robert Jobson also revealed Prince Harry became petulant with staff in the run up to his May wedding.
He is said to have told courtiers in a raised voice: “What Meghan wants, Meghan gets.”
A Kensington Palace spokeswoman refused to comment.
The two made their first appearance together a month after May’s Royal Wedding at an event in Cheshire.