In an unearthed video from 2010 - Prince William and Kate's first joint interview - the Duchess revealed why she was initially apprehensive about meeting the Prince of Wales.
"I was quite nervous about meeting William’s father, but he was very welcoming and very friendly," Kate said.
"It couldn’t have gone easier for me really."
WATCH: Kate Middleton says she was nervous to meetPrince Charles
According toExpress, the 37-year-old has been visiting Queen Elizabeth II's estate in Balmoral ever since meeting Prince William at the University of St Andrews, which enabled her to grow close with Prince Charles (who is married to Camilla Parker Bowles).
His Royal Highness also taught Kate to deer stalk prior to her royal wedding.
In the same interview, William and Kate revealed what it was like for the future Duchess of Cambridge to meet the Queen for the first time.
"I first met the Queen at Peter and Autumn’s wedding [in 2008] and again it was in among a lot of other guests and she was very friendly, it was fine," said Kate (who shares Prince George, Princess Charlotte and Prince Louis with William).
The Duke of Cambridge agreed, adding, "She was very welcoming. She knew it was a big day and everything was going on with Peter and Autumn,
"She had wanted to meet Kate for a while so it was very nice of her to come over and we had a little chat and they got on really well."
Catherine, Duchess of Cambridge, Camilla, Duchess of Cornwall, Prince Charles Prince of Wales and Prince William, Duke of Cambridge at day one of Royal Ascot in 2019
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Expressreported that her Royal Highness maintains a close friendship with Kate to this day and that the two share a love of nature.
In their engagement video, William also revealed that he felt “lucky” with his new in-laws.
"Kate’s got a very close family, and I get on really well with them and I’ve been lucky they’ve been so supportive," he said of his wife's parents.
"Mike and Carole [Kate’s parents] have been loving, caring and really fun, really welcoming towards me.
"So I’ve felt really part of the family and I hope Kate feels the same with my family."