Here is everything we know about Archie's christening, according to the Daily Telegraph.
When is it?
The ceremony will take place this Saturday, July 6, exactly two months after baby Archie was born.
The Duchess of Sussex was reported to have originally planned for a home birth at Frogmore Cottage, but moved to a private London maternity wing in the Portland hospital.
Since then, the new family have lived in their home in the Windsor Great Park in Berkshire.
Two days after his birth, the Duke and Duchess made their first public appearance with Archie at Windsor Castle for a short interview and photocall which saw the newborn cradled by his father.
They have since shared two partial photos of Archie, posted on the couple's Instagram account - SussexRoyal.
The public were treated to a photo of Archie's tiny feet on Mothering Sunday this year, and a photo of Archie in Prince Harry's arms on Father's Day.
The timing of baby Archie's christening is similar to that of his cousins, Prince George and Princess Charlotte, who were also christened almost exactly two months after their birth in 2013 and 2015.
Where is it?
The ceremony will be held at Windsor Castle, one of the Royal family's oldest and most famous residences.
It was originally reported that the ceremony would be held in the castle's St George's Chapel, where the Duke and Duchess of Sussex were married last year and where Harry was christened in 1984.
St George's Chapel has since seen the marriage of Princess Eugenie to Jack Brooksbank, and Lady Gabriella Windsor to Thomas Kingston.
However, the ceremony will actually take place in another private chapel, located within the castle's state apartments.
The chapel seats around 30 people, leaving plenty of room for the family's 25 guests.
The private chapel is best known for being the source of the 1992 fire at Windsor Castle, after which it was fully renovated.
Unlike St George's Chapel, which seats around 800 people, the private chapel will house a smaller and more intimate ceremony, away from the crowds of spectators that gather outside St George's during important events.
Windsor Castle will be open as normal to the public this weekend, and the weather is expected to be warm, so the castle is likely to be busy.
Excited well-wishers are however unlikely to catch a glimpse of baby Archie, since the state rooms wing of the castle is inaccessible to the public.
Who will attend the ceremony?
It is expected that the Archbishop of Canterbury, Justin Welby, will carry out the baptism.
As the Primate of All England, the task of welcoming a new royal member of the Church falls to Archbishop Welby, who also baptised and confirmed the Duchess of Sussex into the Anglican faith, two months before she married Prince Harry in March 2018.
The Archbishop also carried out Prince George's christening in October 2013, Princess Charlotte's in July 2015 and Prince Louis's in July 2018.
Godparents
A key element of a christening is the appointment of godparents, who will pledge to look after Archie and provide him with spiritual guidance throughout his life.
However, in a marked departure from traditional royal christenings, the couple will keep the identity of the godparents a secret.
The couple have insisted that the names of his godparents will remain hidden "in keeping with their wishes".
Previous royal christenings have generally seen the palace announce limited details for the public historic record including the names of the family and friends entrusted with the infant's spiritual wellbeing.
If the Sussexes follow the Cambridges' example they will choose between five and seven.
Some commentators have speculated that some of the Duchess's transatlantic friends could be godparents.
Serena Williams, who is competing at Wimbledon this week, has been tipped as a possible godparent.
Jessica Mulroney, a Canadian fashion stylist, has also been suggested.
However, Church of England rules dictate that godparents must be baptised themselves before they can accept the role.
While the Church does not specify the Christian denomination to which godparents should be affiliated, it does require them to be Christians.
That would count out Ms Mulroney, who is Jewish.
Another of the couple's VIP friends is eligible for the role of godparent and is understood to be well-respected by the Sussexes.
Oprah Winfrey announced earlier this year that she will produce a documentary series about mental health with the Duke and Duchess, set to be released in 2020.
She has also been open about her Christianity, which would qualify her to offer spiritual advice to Archie in the future.
George and Amal Clooney, who attended last year's royal wedding, have already dismissed rumours that Mr Clooney had been earmarked for one of the godparent roles.
The Hollywood actor told Jimmy Kimmel Live, a US talk show, that it would be a "bad idea" to make him godfather to baby Archie, as he is busy enough as a father of twins.
Prince George has seven godparents, including Prince William's cousin, Zara Tindall, and a number of close friends of the couple.
Julia Samuel, a close friend of Princess Diana, was named one of George's godparents, and it is likely that the Sussexes will pick a godparent close to Prince Harry's late mother.
Lady Julia Fellowes, Diana's older sister, was one of the first to meet baby Archie, visiting before either Prince William or Prince Charles.
Guests
The ceremony is expected to be a small affair, with no more than 25 guests attending.
The group will consist of family and close friends.
One notable absence will be the Queen, who will not be attending due to prior engagements.
The Queen and Duke of Edinburgh also missed Prince Louis's christening last year, but did attend both Prince George's and Princess Charlotte's ceremonies.
It is unknown whether the Duke of Edinburgh will attend.
Prince Philip has been largely absent from the public eye since he was involved in a car crash earlier this year in Sandringham.
The Duke was pictured at an event on the Sandringham estate late last month, but usually does not accompany the Queen on official engagements.
The Duke and Duchess of Cambridge will be at the ceremony, and it is expected that Prince Charles and Camilla, the Duke and Duchess of Cornwall, will attend.
The Duchess of Sussex's mother, Doria Ragland will be there for her grandson, alongside other guests and friends from the United States.
Can I watch it?
The Duke and Duchess of Sussex have demanded that Archie's christening remain "private", so access to the ceremony for members of the public is likely to be extremely restricted.
While a small media presence is sometimes allowed outside royal christenings, journalists have been told that Archie's day will be closed. There will be no opportunity to take photographs or observe guests.
The Duke and Duchess of Sussex will travel to the chapel within Windsor Castle from Frogmore Cottage, their home within the castle's grounds.
The Duke and Duchess of Cambridge and the Duke and Duchess of Cornwall are expected to arrive at the castle in the morning.
The ceremony will not be televised and the media has not been invited to any events before or after the christening.
Keen royal watchers will instead have to wait until Sunday, when an official photograph of Archie and his parents, taken by a private photographer, will be released to the media and on the Duke and Duchess's joint Instagram account.
What is the significance of the christening?
The christening will mark Archie's formal admission to the Church of England.
During the ceremony the Archbishop of Canterbury will appoint Archie's godparents, who have been chosen by the Duke and Duchess of Sussex.
The ceremony is important for the Royal family, and marks the link between the Christian faith and the United Kingdom, cemented by the Queen's dual role as head of the Church of England and head of state.
Christenings bring with them their own history and traditions for the royals, including the dress that Archie is expected to wear on Saturday and the ceremony's location at the heart of Windsor Castle.
What will Archie wear?
All of Queen Elizabeth's great-grandchildren have worn a replica of the Honiton lace christening gown commissioned by Queen Victoria for the baptism of her first child, Princess Victoria, in 1841.
It was worn by 62 royal babies over the course of 163 years, including Prince Charles, Prince William and Prince Harry. It was retired in 2004 after it was decided the dress was too delicate to continue being used in services.
A replica gown was created by Angela Kelly, the Queen's wardrobe advisor, and was worn by Archie's cousins, Prince George, Princess Charlotte and Prince Louis in their christenings.
It is expected, but not confirmed, that Archie will also wear the replica gown for his ceremony on Saturday.
