In 2013, Prince Louis' older brother, Prince George, was also christened by Welby at the Chapel Royal.
Now eight weeks old, he was born in London on 23 April, weighing 8lb 7oz.
James Brookes, a royal expert, told British tabloid The Daily Express that pictures of Prince Louis' christening were likely as the Duke and Duchess of Cambridge sought to compromise between their desire for privacy and public desire for information about the event.
He will wear a cream lace and satin gown also used for the christenings of his elder siblings, Prince George and Princess Charlotte. "His big sister, Lady Louise Windsor, had been the last royal to wear the original gown", the site notes.
He was on his best behaviour, blowing bubbles beforehand and being quiet and peaceful afterwards.
So far, the public have had just two glimpses of Kate and William's youngest child. The 45-minutes service, was also attended by her now father-in-law, Prince Charles, and Camilla, the Duchess of Cornwall.
Prince William and Kate, the Duke and Duchess of Cambridge, have named their third child. Prince Louis will be christened by The Archbishop of Canterbury, the Most Reverend Justin Welby'.
Details of the godparents are yet to be announced but it's thought Prince Harry and new bride Meghan Markle won't get called up to the duty.