Kate Middleton put on a ‘game face’ in order to ‘power through’ at King’s birthday celebrations, a body-language expert says

Her attendance was only announced the evening before and came as something of a surprise as it was believed that she would be stepping away from royal duties amid undergoing “preventative chemotherapy.”

The mother-of-three joined other senior members of the British royal family for all public-facing parts of the ceremony. She was seen arriving at Buckingham Palace with her husband, Prince William, and their children.

Speaking on behalf of Slingo, body-language expert Darren Stanton said that the first glimpse of the princess set the tone for the annual royal event, which she has never missed since joining the royal family in 2011.

“Looking at the first photograph of Kate Middleton and Prince William heading to the ceremony together, Kate is using a masking smile. It’s her game face,” he said.

“She’s using this as a way to power through and do the best she can,” Stanton said, noting that “her composure appears calm and collected on the outside.”

He also observed that Kate’s “smile isn’t completely engaged,” which may suggest that she’s not feeling completely at ease.

“Internally, she’s feeling a sense of wanting to make people proud, but she is also feeling nervous – which is understandable.”

During the procession to and from the Horse Guards Parade, Stanton said that it was “significant” that Kate chose only to wave at the crowds a few times.

“It makes her come across as quite stoic,” he said.

Kate and her children Prince George, 10, Princess Charlotte, 8, and Prince Louis, 5, watched on from Glass State Coach as William rode horseback for the ceremony.

“It appears she’s trying to avoid attention with quite a bit of distance,” he noted.

“Today is about the King and Kate adopting a reserved and low-key manner that reinforces that,” said Stanton.

Later in the day, Kate was seen in high spirits as she joined other royal family members on the balcony of Buckingham Palace to greet the crowd and watch the military flypast.

It was unknown whether Kate would appear on the balcony or not, as the palace had noted ahead of time that while Kate was expected, these plans were subject to change on short notice.