Prince William attended the State Opening of Parliament on behalf of the Queen this week.
The Duke of Cambridge acted as the 96-year-old's Counsellor of State, as he followed alongside father Charles to attend the occasion.
Body language expert, Adrianne Carter, tells the Daily Star that the Duke had a visible fall in confidence at the ceremony, unlike his other public engagements.
"He is not always as confident at 'officialdom' as he is when interacting with real people."
She noted: "Charles looks like he's been ready to do this for a long time and is very natural and comfortable.
"Camilla and William looks more nervous by the way they're holding themselves and their posture."
Of the Duke, she added: "William keeps his head bowed a lot, which is a submissive way of being."
Prince William was feeling "the weight of the occasion" as he opened Parliament on the Queen's behalf alongside his father.