Prince Harry and Meghan Markle made their first public appearance in the U.K. since Megxit at the Platinum Jubilee celebrations. They joined the rest of the royals for a Thanksgiving service at St. Paul's Cathedral on Friday, June 3, where according to a body language expert, the duke appeared very nervous.

The Duke and Duchess of Sussex were greeted with cheers from the public when they arrived for the service, but the reception inside was far less welcoming, according to royal expert Russell Myers.

Speaking to the Australian morning show "Sunrise," he said, "It was very, very frosty inside the church. You could cut the atmosphere with a knife."

He observed from the televised service that the brothers "didn't lock eyes or make eye contact at all." Prince Harry "was craning his neck to look at William and William didn't look back at him."

Myers said, "I think there's still a lot of bad atmosphere going on and there needs to be a bit more water under the bridge until those brothers come back together."

Meanwhile, body language expert Judi James said that the Duke of Sussex appeared very anxious during the Thanksgiving service. His gestures and actions reportedly indicated that his anxiety levels were "quite high."

She said that holding his head down could have also been a sign of submission. He also frequently touched his clothes and attempted to make jokes, which could be a sign of anxiety.

"It was like he had agreed to be the invisible man there to some extent," she told The Sun adding, "There was also a return of the slightly haunted eye expression we used to see before they moved abroad." At one point, the Duchess of Sussex was said to have told her husband, "Yeah, we'll be fine" as cameras showed him reaching into his suit pocket.

Prince William and Kate Middleton appeared calm and assured, whereas Prince Harry and Meghan Markle reportedly looked uneasy. The duke was at times seen leaning forward with his head hanging low, while the duchess leafed through her order of service and had a fixed smile on her face.

Returning royals Prince Harry and his wife Meghan attended a thanksgiving church service on Friday