The expert commented Sophie seemed comfortable stepping into her role as a senior member of the Royal Family.
This may have been helped by her close relationship with her mother-in-law, the Queen.
Kate Middleton also avoided public events before she tied the knot with Prince William.
Over the last 10 years, however, she has become a popular member of the Royal Family.
When she has been seen with Sophie, the royal women seem to get on well, Judi commented.
When they were seen, Judi suggested Sophie was on hand to offer guidance and advice to her niece-in-law.
She concluded: “Many of the poses of the two women together show Sophie face-checking Kate with quite strong bouts of watchful-looking eye contact to suggest she’s taking a semi-maternal approach.
“However, she also has raised brows and what’s called a ‘pinging’ smile that implies she wants to ensure Kate is enjoying herself.
“There is some mirroring when the two women walk together but it’s primarily Sophie projecting the stronger signals of relaxed confidence while Kate smiles happily at her side.”