Prince Harry appeared "nervous" and showed signs of "anxiety" while getting ready to speak at an event to honour of his later mother, Princess Diana, according to one body language expert.

The Duke of Sussex appeared on stage for The Diana Awards in New York on Monday, which is a charity that recognises young people who make positive social change.

The award was established in 1999 by the Government in memory of Diana, Princess of Wales.

The prince appeared on stage, alongside two winners of the awards, to deliver a speech on mental health and climate.

Despite doing many speeches throughout his life as a member of the Royal Family, Harry appeared "nervous" as he tugged on his blazer, cracked his knuckles and pulled on his tie, a body language expert has said.

Judi James said that these gestures were sure signs of "nervousness" and "anxiety" but that he may have been aware he was displaying these signals.

Responding to a video of him at the event, she said: "Incredibly Harry performed no less than 19 gestures or rituals of anxiety or nervousness in the space of twenty-eight seconds here.

"He is known to be a nervous speaker but he has rarely, if ever, displayed this amount of concentrated signals and the fact he is doing them on the stage rather than more privately off-stage only makes the body language look more curious, almost as though he is happy or comfortable projecting a message of inner anxiety."

Speaking about the Duke's "anxiety rituals," Judi explained: "Self-touch, checking rituals like this suggest nervousness and a desire to create small barriers plus some degree of self-comfort.

"Harry tucks his jacket as he sits before adjusting his tie, which would both be common procedures. But then he pulls at his tie at least four more times and yanks at his jacket on three more occasions.

"He also bounces in his chair, rubs his knees with both hands, squirms in his seat, performs two lots of leg judders and finishes by meshing his fingers to crack his knuckles, rub his thumbs together and then rub them onto his mouth."

But it could have been a way of " revving up towards a performance" or the subject matter " created some strong emotions" in him.