Surprising joke that Kate Middleton made at Prince Louis' christening

Monday was a big day for the Duke and Duchess of Cambridge. Their last born son, Prince Louis, was christened.

As the new family of five arrived at St. James’s Palace, Duchess Kate got to have a word with the Archbishop of Canterbury Justin Welby according to Twitter.

Kate spoke to the Archbishop of Canterbury Justin Welby as he greeted her and her family at Chapel Royal. She was holding a sleeping Prince Louis in her arms.

Noticing this, Welby commented that the little boy looked 'relaxed and peaceful.' The Duchess responded with a joke that most, if not all, parents can relate to.

For more on this story go to our Twitter account @amomama_usa. Kate replied that 'I hope he stays like this.'

Welby then greeted the baby's grandfather, the Prince of Wales, and his wife Camilla as the Royal Family made their way into the palace. Prince William, who was holding Prince Louis' brother George with his left hand and sister Charlotte with his right, was also present.

Welby crouched down to speak to Charlotte, who gave the clergyman a very polite handshake. It's the first time the Cambridge’s were seen together as a family of five.

For the occasion, Kate wore a dress by designer Alexander McQueen. Little Louis was dressed in the same cream gown used for his older sibling’s christenings.

Earlier on, Welby had expressed his joy at being asked to conduct the service. He said, 'I’m delighted and privileged to be christening Prince Louis today – a precious child made in God’s image, just as we all are.’

Louis Arthur Charles was born in the private Lindo Wing of St Mary's Hospital in Paddington, London. He was born on April 23, St. George's Day, weighing 8lb 7oz.

Prince Harry and Duchess Meghan, Louis’ uncle and aunt were also there. His grandfather and grandmother, Prince Charles and Camilla, also attended the ceremony.

The Queen and Duke of Edinburgh were unable to attend.