The son of the Duke and Duchess of Sussex will be christened by the Archbishop of Canterbury in a private ceremony on Saturday.
Archie Harrison Mountbatten-Windsor will be baptised in front of close family and friends in the private chapel at Windsor Castle.
The Duke and Duchess of Cambridge have been seen arriving but were not thought to have their children with them.
The Queen is not attending due to a prior engagement.
Meghan’s mother, Doria Ragland, is expected to attend, as is Prince Charles and the Duchess of Cornwall.
The royal couple have opted to exclude the press and the public from the day and chose not reveal the names of Archie’s godparents.
Instead of having press photographers, fashion photographer Chris Allerton, who took their wedding photos, will capture the special moment.
However, Prince Harry and Meghan will be following some royal traditions.
Archie will wear a handmade replica of the royal christening robe which was made for Queen Victoria’s eldest daughter.
The robe, which has been worn by royal infants on the occasion of their christening for the last 11 years, was made by Angela Kelly, dressmaker to the Queen.
The ornate Lily Font, commissioned by Queen Victoria and Prince Albert for the baptism of their first child Victoria, Princess Royal, in 1841, will also be used – as will water from the River Jordan.
Those hoping for more than a glimpse of the royal christening today will be disappointed.
There will be no television coverage, nor have press photographers been invited.
Some privately-taken photographs are expected later this afternoon.
Normally a list of godparents would be released, but this time, says the palace, in keeping with the wishes of those chosen by Harry and Meghan, their names will be kept private.
It all points to a very different royal event, part of the continuing desire by the Duke and Duchess to raise their son Archie out of the spotlight.
Coming so swiftly after the revelation that almost £2.5m of tax payers money was spent renovating a property for Harry and Meghan – it has raised questions about visibility.
The previous understandings about public access to royal events appear to have been abandoned by a couple determined to do things their own way.