Prince Harry Snuck a "Thunderous" Look at Estranged Brother Prince William During the Coronation Ceremony: Body Language Expert

Prince Harry seemed to have quite a fun time at King Charles' Coronation on Saturday—especially as he chatted to his cousins Princess Eugenie and Princess Beatrice, as well as their respective husbands.

The Duke of Sussex' good humor might have come as a bit of a surprise to royal watchers, who potentially expected him to seem out of sorts as he reunited with estranged family members.

But while Harry made sure to enjoy the moment as much as he could, he couldn't help but look pretty wary as he stole a glance at Prince William, with whom he reportedly doesn't really have a relationship at all these days.

"Despite his act of bravado there were some more telling moments and expressions from Harry, like this pensive one when he seemed to glance across at William," body language expert Judi James told Fabulous, as she analyzed images of Harry looking at William from two rows behind him in Westminster Abbey during the ceremony.

"William is clearly not about to look back here and Harry’s severe side-eye glance suggests he’s sneaking this thunderous look almost unintentionally."

James went on to explain that, even if Harry was trying to play it cool, his instincts could have taken over in this moment.

"When we tell ourselves not to do something, the brain only tends to hear the suggestion without processing the 'don’t' command, suggesting the more Harry was telling himself not to look across at his brother the more he couldn’t stop," the expert claimed.

Still, throughout most of his much anticipated appearance at the historic event, the duke betrayed no ambivalence about being there.

"If we were expecting some signals of anxiety, reflection or even the look of a penitent, Harry decided to disappoint the critics," James observed.

"He arrived in the guise of Harry the joker, miming Eugenie’s heavily pregnant bump to make his cousin and her husband Jack laugh, before falling back to walk in alone, not in a way that looked solitary or shameful, but with a jaunty stride and beaming grin as he spoke or acknowledged people in the congregation like old friends.

"It was a very counterintuitive act of body language defiance and resilience and a very different, cockier Harry than we have seen on his most recent visits to the UK."

In case you somehow haven't heard this by now, Prince Harry and his wife Meghan Markle have had a very fraught relationship with the Royal Family at large since they left their royal roles behind and swapped them for sunny California.

Relations have seemed to especially sour since the release of Harry's memoir Spare, which hit out at Prince William most especially, but also made shock revelations about King Charles, Princess Kate and Queen Camilla.

Reportedly, William and Harry haven't spoken since Queen Elizabeth's funeral last September, and seem unlikely to reconcile any time soon.