The service will be conducted by the Archbishop of Canterbury, the Most Reverend Justin Welby, who also baptized Meghan and officiated her nuptials to rince-ha.
Prince Louis Arthur: FIRST official pictures Sun, May 6, 2018 Prince Louis Arthur: FIRST official portrait with Princess Charlotte.
Kensington Palace said Louis will be baptised on July 9 when he is 11 weeks old.
As we've seen Prince William's style evolve from perfectly pressed overalls as a toddler to his sweater and jeans adolescent years to his dapper uniforms and now his uber cool-dad style, we can say with confidence that Will has come a long way since his world debut.
It comes after Charlotte donned a pink floral dress while joining Kate and brother George to watch William take part in a polo match last week.
The names of Princes Louis' godparents are likely to be announced on the day.
Prince Louis is following in his new aunt, Meghan Markle's footsteps. The original garment was created for Queen Victoria for the christening of her eldest daughter, Princess Royal Victoria, but is now considered too fragile for use.
If his siblings' ceremonies are anything to go by, Prince Louis' christening will be a private affair.
A royal expert told Express that Prince William and Kate will opt to have a private christening for their youngest son.