Millions of people across the world may have tuned in to watch the Prince and Princess of Wales say ‘I do’ at Westminster Abbey, but they never got to find out exactly what else the couple whispered to one another at their royal wedding.

Lip readers have analysed the couple’s interaction at the altar with Kate’s father Michael Middleton, but little was known about their first words as husband and wife.

Princess Kate and Prince William shared some private words in their carriage ride to Buckingham Palace

Shedding light on their sweet post-ceremony interaction, lip reader Tina Lannin told CBS News that Prince William had a surprising three-word comment to his new bride Kate in the carriage procession through the streets of London on their way to Buckingham Palace.

Amid the chaos of the cheering crowds, William couldn’t tear his eyes away from his wife, telling her: “You look happy.” She reportedly replied: “Yes! Are you happy?” and he said: “Yes. Very!”

Prince William and Kate got married at Westminster Abbey in 2011

These were not the first words that came to mind in the carriage, however. William also reportedly noted the “mad” atmosphere of the day and gave Kate tips on royal etiquette.

“I don’t think you should bow quite yet. I think you should just bow your head, okay?” he said, before adding: “I hope I remember… It’s mad, it’s mad! Oh my goodness it… really loudly here (unclear) these people are clapping.”

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Earlier in the day, he was caught on camera admiring his bride in her £250k Alexander McQueen lace wedding dress and Cartier Halo Tiara as she walked down the aisle on the arm of her father. As Kate halted in front of William, he sweetly called her “beautiful” and joked to his soon-to-be father-in-law about the 2,000-strong guest list.

Prince William also joked to his father-in-law Michael Middleton at the altar

“We’re supposed to have just a small family affair,” he said, according to lip readers.

Kate and William’s love story

During their engagement interview in 2010, King Charles’ son gushed about their love story, which began at St Andrews University.

“When I first met Kate, I knew there was something very special about her. I knew there was possibly something that I wanted to explore there.

“We ended up being friends for a while and that just sort of was a good foundation. Because I do generally believe now that being friends with one another is a massive advantage. And it just went from there.”

They briefly split in 2007 before rekindling their romance three months later, and they got engaged in Kenya in 2010.

The couple are now parents to Prince George, Princess Charlotte and Prince Louis.