No announcement identifying the godparents has been made, but some are speculating that Prince Harry and Meghan Markle may have chosen Canadian stylist Jessica Mulroney, daughter-in-law of former prime minister Brian Mulroney.
Royal photographer Chris Allerton released two sets of photo for baby Archie's baptism, which were highlighted on the Sussex Royal Instagram page. Also in the family picture were late Princess Diana's sisters, Lady Jane Fellowes and Lady Sarah McCorquodale.
A family photo inside the castle's Green Drawing Room shows Harry and Meghan sitting with their child alongside the Duchess of Cornwall and the Duchess of Cambridge. The original Royal Christening Robe, made of fine Honiton lace lined with white satin, was commissioned by Queen Victoria in 1841 and first worn by her eldest daughter.
The replica has been worn by royal infants at christenings for the last 11 years.
Meghan and Prince Harry don't want the same thing for their child.
Sitting on the right of Archie's parents in the official christening portrait is Duchess of Cambridge and aunt, Kate Middleton. Queen Elizabeth and Prince Philip were sadly absent from the occasion due to a prior engagement, which was also the case when Prince Louis was christened in 2018.More news: Our First Look at Samsung's Galaxy Note 10 and Note 10+
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Since tragically losing their beloved mum at such a young age, Prince Harry and Prince William have always kept Princess Diana in the forefront of their minds - even more so the special events of their lives.
Members of the St. George's Chapel Choir performed.
One family portrait included Prince Charles, Meghan's mother Doria Ragland and Prince William and his wife, Kate.
Meghan was left devastated when she was forced to leave her other rescue dog, a labrador-shepherd mix Bogart, in Toronto when she moved to the United Kingdom to live with Prince Harry.
The Duchess of Sussex's estranged father has wished his grandson "health and happiness" from afar, as Archie Mountbatten-Windsor's family and new godparents rallied around a remarkably secretive operation for his christening.
Mr Markle has not met his son-in-law Harry or his new grandson. Archie is seventh-in-line to the British throne.
In the caption the Sussexes said they felt "happy to share the joy of this day with members of the public".