Prince Charles, Kate Middleton's relationship unveiled by expert

Prince Charles and Kate Middleton's relationship set off during her 2011 wedding reception where he said in a speech: “We are lucky to have her.”

Body language expert Judi James broke down the Duchess of Cambridge and Prince of Wales’ interaction over the years.

She said that their movements indicating having a formal link as Kate is a “catalyst” in Charles’ life.

"Kate’s role in Prince Charles’s life appears to be that of a catalyst rather than a friend or kindred spirit," she said.

"There are rarely if ever any signals of the kind of easy-going, spontaneous warmth he shares with his niece Zara. There’s nothing to suggest a meeting of minds between Charles and Kate.

"When they are seen walking together Charles’s body language suggests he might be at a bit of a loss in terms of easy-going conversation.

"His hand is shoved into his pocket to suggest some feelings of awkwardness and he looks away from Kate with a dipped head and the spatial gap between them will often look quite pronounced."

She added that Kate's respectful demeanor is "exactly what he needs" as she ensures caution with everything she does.

"Kate’s body language always looks respectful and careful with her father-in-law.

"Although her air of polite caution might not resonate with Charles it is clear she is exactly what he needed.

"She is the kind of calming and non-disruptive daughter-in-law that will help hold the fractured royal firm together by never putting a foot wrong."