Prince Charles is a doting grandfather to all of his grandchildren. But his body language differs when he’s around them.

This week, Prince William and Prince Harry uploaded a special tribute to their father on the occasion of his 71st birthday. On their respective Instagram accounts, the royal siblings’ posts featured their children.

While speaking with Express, body language expert Judi James compared Prince Charles's interaction with Prince Louis and Archie Harrison in their respective snaps.

James said that Prince Charles is tentative when he’s with Archie, and he’s more tactile when he’s with Prince William and Kate Middleton’s youngest child.

“Archie was barely seen out of Harry’s arms during his first few months and with Harry gazing with a besotted smile at Archie’s little face in his arms, Charles’s approach looks far more tentative, as though he doesn’t want to disturb either of them,” she said.

Prince Charles is smiling from ear to ear in both photos, which prove that he’s a doting grandfather to his two youngest grandchildren. In Prince Louis’ photo with Prince Charles, Middleton looks as though she’s keen to make sure that the two male royals are enjoying their special moment.

“The way Kate holds [Louis] to her own torso but with his body facing his grandfather suggests she is keen to the point of determined to get Charles more involved here. She even studies her father-in-law’s face to watch his reaction as he plays with Louis, where Harry quite naturally looks lost in a bubble of love with his first-born,” she explained.

In Prince Harry’s photo with Archie, it seems as though the Duke of Sussex is very protective of his son. As such, Prince Charles seems a little distant with Archie in the photo.

Meanwhile, James said that Prince Charles’ upbringing is impacting his relationship with all of his grandchildren.

“Like a lot of fathers from a more traditional era, Charles has often appeared to treat his children and grandchildren with an air of fond but slightly curious detachment,” she said.

Britain's Prince Charles is visiting New Delhi on a day the Indian capital's pollution has reached 'emergency' levels
Britain's Prince Charles is visiting New Delhi on a day the Indian capital's pollution has reached 'emergency' levels AFP / Money SHARMA