Captain Mark Phillips, now 69, from Tetbury, Gloucestershire, married Princess Anne, 68, in 1973.
The Olympic equestrian had two children with Anne, Peter and Zara.
Judi said: “(Jack’s) amiability signals look rather similar to Captain Mark Philips’s when he married into the royal family but unlike Mark it could be that Jack is given an royal induction, being welcomed by a much more empathetic and less intimidating generation of younger royals.
“Eugenie and Jack’s body language shows a younger couple rather sweetly in love, especially Jack who lacks the signals of alpha machismo that Andrew and Harry learnt in the forces.”
Prince Andrew has an impressive career in the militry behind him.