The Queen had "reached her limit" with the Duchesses - formerly known as Meghan Markle and Kate Middleton - according to reports from the US.
A source told Us Weekly the Queen was fearful for the overall relationship of the Royal Family and is glad both Duchesses put their differences aside.
Kate and Meghan recently put on a friendly display as they arrived for a Christmas Day church service at Sandringham, with a source revealing the Queen "desperately wanted Meghan and Kate to make up and she got her wish."
As the royals gathered at the Queen's home in Sandringham for the Christmas period, the source said: "Being under the same roof meant that they couldn't avoid each other."
According to The Sun, Kate and Meghan enjoyed a game of Scrabble together.