Meghan added: "It's surreal. It wasn't like some big moment of like, 'Now you're going to meet my grandmother," Meghan said. "I didn't know I was going to meet her until moments before."

"And I remember we were in the car and we were driving up and he's like 'You know how to curtsy right?' And I just thought it was a joke."

It was then that the duchess re-enacted the moment she met the late Queen and performed a long and exaggerated curtsy before saying while giggling: "Pleasure to meet you, Your Majesty", while the camera showed Harry.

Body language expert Jesús Enrique Rosas noted the duke's discomfort and analysed Harry's appearance in the clip on his Youtube channel.

He said: "The first part of Harry's reaction tells me that he knew what was coming. He is serious even if Meghan is speaking quickly, joyfully but there's no connection, no empathy in him. He is serious and maybe even angry, notice what happens with his throat, he is swallowing at that moment."

The expert also outlined Prince Harry's "contempt" at Meghan's comments, noting that his face flushed as she performed the exaggerated bow.

"He is looking at Meghan and he displays contempt. A split second after that, he looks away and presses his jaw," the body language expert explained.

He added: "You can see the patches of red on his face are much redder – the cheeks, the bridge of the nose, the temples – it could be that he feels ashamed or angry.

"I'm going to tell you why this is covert anger and not [Harry being] ashamed. If he was ashamed, he would have smiled a bit more, or [had] a nervous laughter.

"But he knew what was coming and he couldn't stand it - that he had that face at the beginning and had that subtle swallow right before Meghan did the curtsy."