Kate met William when they were both students at the University of St Andrews.
The pair got married in 2011 after dating for more than eight years.
Meanwhile, Meghan and Prince Harry met in July 2016.
Camilla ‘extended the hand of friendship’ to Kate and Meghan, royal expert claims
They went on to announce their engagement in November 2017 and tied the knot in May 2018.
The Duke and Duchess of Sussex are now living in California after quitting royal duties in 2020.
Meanwhile, the Duchess of Cambridge recently photographed Prince Charles’s wife for Country Life to mark her 75th birthday.
Royal commentator Daniela Elser said Kate and Camilla had become a “formidable power couple”.
Camilla pictured with Meghan in 2018
Writing for news.com.au, she added: “But something in the last little while has very clearly shifted on this front and somehow Camilla and Kate have become a formidable – and very friendly – power couple.
“Most obviously, they seem to really get on like a house on fire.”
Kate stepped out with Camilla and the Prince of Wales for a rare joint engagement back in February.
Kate stepped out with Camilla and the Prince of Wales for a rare joint engagement back in February
Kate and Camilla share a smile on Garter Day
The Duchesses shared a carriage for Trooping the Colour during the Platinum Jubilee
The two Duchesses also shared a carriage for Trooping the Colour and Garter Day last month.
Ms Elser said Camilla and Kate’s bond is “so remarkable” as it is an “abject departure” in royal history.
She said: “The point is, never before have we seen an alliance quite like this of Kate and Camilla, two women who grew up sans titles and noble lineages and yet in whose hands now rests the future of the monarchy.
“When the sad but inevitable comes when the Queen passes away, the coronation of Queen Camilla and later the arrival of the new Princess of Wales will represent a new era where the two most powerful women in the monarchy are closely aligned.
“Having a Queenly coalition not only willing but happy to work in step will have implications for The Firm as a family and as an institution.”
Source: EXPRESS CO UK