“Charles has always shown signals that suggest self-pity and inner anguish,” she told Express.co.uk.
“As Charles has grown older his features often adopt a kindly, smiling expression with narrowed, wrinkled eyes and lips upturned at the corners.
“His constantly steepled brows throw a touch of anxiety or concern into the mix though, as well as hinting at some self-pity.
“His self-comfort rituals have been a feature for most of his adult life, like the use of pockets and checking gestures, like the cuff-fiddle.”
Princess Anne, on the other hand, has seemed more confident by showing “assertive” body language during engagements, Judi claimed.
The expert added: “Anne’s features tend to involve raised, arched brows and widened eyes and a smile that is either suppressed or tilted down at the corners.
“Her pose tends to be upright and assertive, with her arms down at her sides rather than acting as a partial barrier or self-comforter.”
Princess Anne and Prince Charles are the closest in age of all the Queen’s children.
Despite that, Judi suggested their differences may have been clear from an early age.
She stated: “Growing up he and Anne perfectly defined the chalk-and-cheese sibling relationship, with Charles suffering through his school years while Anne just got on with things.
“As Charles adopted a more academic approach to the life of a future King, Anne became a successful, no-nonsense sportswoman alongside her regular royal duties.
“Her body language signals with her brother Charles suggested – almost from birth – that she was the one who had been gifted all the confidence.
“While Charles looked dreamy, shy and hesitant Anne looked bubbling with happy self-esteem.”
While they may have different personality traits, the expert suggested they have become closer in recent years.
Judi stated: “There were very little if any relationship-defining poses of the pair over the years, although recently there have been clues that suggest they might have been becoming closer.
“Senior royals do seem to have closed ranks around the Queen recently.”
Princess Anne and Prince Charles may have appeared closer because of their shared duty to the Queen.
Their bond may also have grown over the years because of Zara Tindall’s close relationship with her uncle, Prince Charles.
Judi added: “They are beginning to look as though shared goals in terms of their love and sense of duty to their mother and a desire to sustain the image of the royal firm have brought them closer together.
“Also, with the obvious affection that Anne’s daughter Zara seems to have for her uncle Charles.”