In one of the most touching moments of the Coronation, Prince William knelt before his father King Charles to pledge his allegiance before kissing him on the cheek.
And a lip reader has revealed the three heartfelt words the newly-crowned monarch uttered to his oldest son after he made his pledge.
William pledged loyalty to his father in a solemn rite, kneeling to give an oath of allegiance to his father.
He said: "I, William, Prince of Wales, pledge my loyalty to you and faith and truth I will bear unto you, as your liege man of life and limb. So help me God."
He then stood up, touched the crown and gave his father a kiss on the cheek. The King appeared to be moved by his son's gestures, as he nodded and appeared to say a few words to him.
And a professional lip reader told the Mirror that Charles told him: "Thank you, William."
Meanwhile, body language expert Judi James told The Mirror that the pair appeared to have made "a pact to avoid too much eye contact" to avoid Charles being "overwhelmed with emotion".
She said: "Touching body language between Charles and William.
"The two men seemed to have made a pact to avoid too much eye contact during the ceremony, possibly because Charles did look in danger of getting overwhelmed with emotion at some points.
"There was a micro-glance as William tied his cape and then we could see William looking away as he did his pledge, although there was one moment after that when they met eye contact briefly and we got a look of warmth and gratitude from Charles to his son.
"Harry did seem to lift his head and crane his neck to watch this bit of the service."
The Duke of Sussex took his seat in the third row for the coronation of his father the King, two rows behind his brother William.
Harry, wearing medals pinned to his suit jacket, chatted to his cousin Princess Beatrice and her husband Edoardo Mapelli Mozzi as he entered Westminster Abbey on Saturday in the drizzling rain.
He also nodded and smiled to guests as he walked down the nave of the abbey.
It is understood the prince wore what he was asked to wear, which consisted of a dark morning suit and tie.
However, Harry is a Knight Commander of the Royal Victorian Order after being made so by the late Queen in 2015. This means he would be entitled to wear the order's vivid blue mantle.
