Prince Harry kicked off his busy schedule in New York on Monday with a mental health-themed event honoring his late mother, Princess Diana.

The Duke of Sussex joined Diana Award CEO Dr. Tessie Ojo and the two honorees in a panel discussion on “The Global Mental Health Crisis Among Youth” at the Concordia Annual Summit.

Of course, it was not easy for Harry, a father of two with a history of mental health issues, to take up this topic, and one body language expert said it showed in the prince's demeanor.

“Maybe it's the subject of mental health and his mother Diana, a topic that is keen and close to Harry's heart, but Harry's body language was like a world away from the confident, show-off, sock-and-tie-less prince that he had previously done for Kevin Costner.” Judy James told the Mirror.

The expert previously described Harry's appearance at the One805Live Fall Concert in California over the weekend as “rock star-like,” which she described as a stark contrast to the royal's somber demeanor in New York.

“When he takes his seat on stage here, Harry goes through a nonstop ritual of anxiety,” James said of the Duke's behavior at the Concordia Summit.

“His expression is not smiling; his face is flushed, as if his emotions are running high. He sucks in his lips, the expression in his eyes suggests sadness, then finally frowns and stares forward in concentration.

James continued. 'His hands rub his knees in a ritual of self-comfort, like a little dance of the feet, rubbing them a couple of times.'

“When he combines his fingers or cracks his knuckles, he almost seems to want to project his inner emotional state. Rubbing his thumbs together is another self-comforting ritual, but then he very deliberately rubs both thumbs over his mouth, suggesting introspection and tension.

On Monday, Harry attended a second event related to his mother's life's work, a reception for the HALO Trust, a charity for landmine clearance that was close to Diana's heart.

While in the City, Harry will also attend events for African Parks, Travalist, and the Archwell Foundation.